Saturday, May 31, 2008

Geographic Information System:GIS

 Geographic information system (GIS) technology can be used for scientific investigations, resource management, and development planning. For example, a GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, or a GIS might be used to find wetlands that need protection from pollution.
What is a GIS?
A GIS is a computer system capable of capturing, storing, analyzing, and displaying geographically referenced information; that is, data identified according to location. Practitioners also define a GIS as including the procedures, operating personnel, and spatial data that go into the system.
How does a GIS work?
The power of a GIS comes from the ability to relate different information in a spatial context and to reach a conclusion about this relationship. Most of the information we have about our world contains a location reference, placing that information at some point on the globe. When rainfall information is collected, it is important to know where the rainfall is located. This is done by using a location reference system, such as longitude and latitude, and perhaps elevation. Comparing the rainfall information with other information, such as the location of marshes across the landscape, may show that certain marshes receive little rainfall. This fact may indicate that these marshes are likely to dry up, and this inference can help us make the most appropriate decisions about how humans should interact with the marsh. A GIS, therefore, can reveal important new information that leads to better decisionmaking.
Many computer databases that can be directly entered into a GIS are being produced by Federal, State, tribal, and local governments, private companies, academia, and nonprofit organizations. Different kinds of data in map form can be entered into a GIS . A GIS can also convert existing digital information, which may not yet be in map form, into forms it can recognize and use. For example, digital satellite images can be analyzed to produce a map of digital information about land use and land cover . Likewise, census or hydrologic tabular data can be converted to a maplike form and serve as layers of thematic information in a GIS.
Data capture
How can a GIS use the information in a map? If the data to be used are not already in digital form, that is, in a form the computer can recognize, various techniques can capture the information. Maps can be digitized by hand-tracing with a computer mouse on the screen or on a digitizing tablet to collect the coordinates of features. Electronic scanners can also convert maps to digits. Cordinates from Global Positioning System (GPS) receivers can also be uploaded into a GIS.
A GIS can be used to emphasize the spatial relationships among the objects being mapped. While a computer-aided mapping system may represent a road simply as a line, a GIS may also recognize that road as the boundary between wetland and urban development between two census statistical areas.
Data capture—putting the information into the system—involves identifying the objects on the map, their absolute location on the Earth's surface, and their spatial relationships. Software tools that automatically extract features from satellite images or aerial photographs are gradually replacing what has traditionally been a time-consuming capture process. Objects are identified in a series of attribute tables—the "information" part of a GIS. Spatial relationships, such as whether features intersect or whether they are adjacent, are the key to all GIS-based analysis.
Data integration
A GIS makes it possible to link, or integrate, information that is difficult to associate through any other means. Thus, a GIS can use combinations of mapped variables to build and analyze new variables.
Data integration is the linking of information in different forms through a GIS.
For example, using GIS technology, it is possible to combine agricultural records with hydrography data to determine which streams will carry certain levels of fertilizer runoff. Agricultural records can indicate how much pesticide has been applied to a parcel of land. By locating these parcels and intersecting them with streams, the GIS can be used to predict the amount of nutrient runoff in each stream. Then as streams converge, the total loads can be calculated downstream where the stream enters a lake.
Projection and registration
A property ownership map might be at a different scale than a soils map. Map information in a GIS must be manipulated so that it registers, or fits, with information gathered from other maps. Before the digital data can be analyzed, they may have to undergo other manipulations—projection conversions, for example—that integrate them into a GIS.
Projection is a fundamental component of mapmaking. A projection is a mathematical means of transferring information from the Earth's three-dimensional, curved surface to a two-dimensional medium—paper or a computer screen. Different projections are used for different types of maps because each projection is particularly appropriate for certain uses. For example, a projection that accurately represents the shapes of the continents will distort their relative sizes.
Since much of the information in a GIS comes from existing maps, a GIS uses the processing power of the computer to transform digital information, gathered from sources with different projections, to a common projection .
An elevation image classified from a satellite image of Minnesota exists in a different scale and projection than the lines on the digital file of the State and province boundaries.The elevation image has been reprojected to match the projection and scale of the State and province boundaries.
Data structures
Can a land use map be related to a satellite image, a timely indicator of land use? Yes, but because digital data are collected and stored in different ways, the two data sources may not be entirely compatible. Therefore, a GIS must be able to convert data from one structure to another.
Satellite image data that have been interpreted by a computer to produce a land use map can be "read into" the GIS in raster format. Raster data files consist of rows of uniform cells coded according to data values. An example is land cover classification.Raster files can be manipulated quickly by the computer, but they are often less detailed and may be less visually appealing than vector data files, which can approximate the appearance of more traditional hand-drafted maps. Vector digital data have been captured as points, lines (a series of point coordinates), or areas (shapes bounded by lines).An example of data typically held in a vector file would be the property boundaries for a particular housing subdivision.
Data restructuring can be performed by a GIS to convert data between different formats. For example, a GIS can be used to convert a satellite image map to a vector structure by generating lines around all cells with the same classification, while determining the spatial relationships of the cell, such as adjacency or inclusion.
Data modeling
It is impossible to collect data over every square meter of the Earth's surface. Therefore, samples must be taken at discrete locations. A GIS can be used to depict two- and three-dimensional characteristics of the Earth's surface, subsurface, and atmosphere from points where samples have been collected.
For example, a GIS can quickly generate a map with isolines that indicate the pH of soil from test points. Such a map can be thought of as a soil pH contour map. Many sophisticated methods can estimate the characteristics of surfaces from a limited number of point measurements. Two- and three-dimensional contour maps created from the surface modeling of sample points from pH measurements can be analyzed together with any other map in a GIS covering the area.
The way maps and other data have been stored or filed as layers of information in a GIS makes it possible to perform complex analyses.
A crosshair pointer (top) can be used to point at a location stored in a GIS. The bottom illustration depicts a computer screen containing the kind of information stored about the location—for example, the latitude, longitude, projection, coordinates, closeness to wells, sources of production, roads, and slopes of land.
Information retrieval
What do you know about the swampy area at the end of your street? With a GIS you can "point" at a location, object, or area on the screen and retrieve recorded information about it from offscreen files.Using scanned aerial photographs as a visual guide, you can ask a GIS about the geology or hydrology of the area or even about how close a swamp is to the end of a street. This type of analysis allows you to draw conclusions about the swamp's environmental sensitivity.
Topological modeling
Have there ever been gas stations or factories that operated next to the swamp? Were any of these uphill from and within 2 miles of the swamp? A GIS can recognize and analyze the spatial relationships among mapped phenomena. Conditions of adjacency (what is next to what), containment (what is enclosed by what), and proximity (how close something is to something else) can be determined with a GIS .
When nutrients from farmland are running off into streams, it is important to know in which direction the streams flow and which streams empty into other streams. This is done by using a linear network. It allows the computer to determine how the nutrients are transported downstream. Additional information on water volume and speed throughout the spatial network can help the GIS determine how long it will take the nutrients to travel downstream. A GIS can simulate the movement of materials along a network of lines. These illustrations show the route of pollutants through a stream system. Flow directions are indicated by arrows.
Using maps of wetlands, slopes, streams, land use, and soils (figs. 19a-f), the GIS might produce a new map layer or overlay that ranks the wetlands according to their relative sensitivity to damage from nutrient runoff.
Data output
A critical component of a GIS is its ability to produce graphics on the screen or on paper to convey the results of analyses to the people who make decisions about resources. Wall maps, Internet-ready maps, interactive maps, and other graphics can be generated, allowing the decisionmakers to visualize and thereby understand the results of analyses or simulations of potential events.
Framework for cooperation
The use of a GIS can encourage cooperation and communication among the organizations involved in environmental protection, planning, and resource management. The collection of data for a GIS is costly. Data collection can require very specialized computer equipment and technical expertise.
Standard data formats ease the exchange of digital information among users of different systems. Standardization helps to stretch data collection funds further by allowing data sharing, and, in many cases, gives users access to data that they could not otherwise collect for economic or technical reasons. Organizations such as the University Consortium for Geographic Information Science and the Federal Geographic Data Committee seek to encourage standardization efforts.

GIS through history
Some 35,000 years ago, Cro-Magnon hunters drew pictures of the animals they hunted on the walls of caves near Lascaux, France. Associated with the animal drawings are track lines and tallies thought to depict migration routes. These early records followed the two-element structure of modern geographic information systems (GIS): a graphic file linked to an attribute database.
Today, biologists use collar transmitters and satellite receivers to track the migration routes of caribou and polar bears to help design programs to protect the animals. In a GIS, the migration routes were indicated by different colors for each month for 21 months.Researchers then used the GIS to superimpose the migration routes on maps of oil development plans to determine the potential for interference with the animals.

Researchers are working to incorporate the mapmaking processes of traditional cartographers into GIS technology for the automated production of maps.
One of the most common products of a GIS is a map. Maps are generally easy to make using a GIS and they are often the most effective means of communicating the results of the GIS process. Therefore, the GIS is usually a prolific producer of maps. The users of a GIS must be concerned with the quality of the maps produced because the GIS normally does not regulate common cartographic principles. One of these principles is the concept of generalization, which deals with the content and detail of information at various scales. The GIS user can change scale at the push of a button, but controlling content and detail is often not so easy. Mapmakers have long recognized that content and detail need to change as the scale of the map changes. For example, the State of New Jersey can be mapped at various scales, from the small scale of 1:500,000 to the larger scale of 1:250,000 and the yet larger scale of 1:100,000 ,but each scale requires an appropriate level of generalization .
Site selection
The U.S. Geological Survey (USGS), in a cooperative project with the Connecticut Department of Natural Resources, digitized more than 40 map layers for the areas covered by the USGS Broad Brook and Ellington 7.5-minute topographic quadrangle maps . This information can be combined and manipulated in a GIS to address planning and natural resource issues. GIS information was used to locate a potential site for a new water well within half a mile of the Somers Water Company service area.
To prepare the analysis, cartographers stored digital maps of the water service areas in the GIS. They used the proximity function in the GIS to draw a half-mile buffer zone around the water company service area.This buffer zone was the "window" used to view and combine the various map coverages relevant to the well site selection.
The land use and land cover map for the two areas shows that the area is partly developed. A GIS was used to select undeveloped areas from the land use and land cover map as the first step in finding well sites. The developed areas were eliminated from further consideration.The quality of water in Connecticut streams is closely monitored. Some of the streams in the study area were known to be unusable as drinking water sources. To avoid pulling water from these streams into the wells, 100-meter buffer zones were created around the unsuitable streams using the GIS, and the zones were plotted on the map. The areas in blue have the characteristics desired for a water well site.
Point sources of pollution are recorded by the Connecticut Department of Natural Resources. These records consist of a location and a text description of the pollutant.To avoid these toxic areas, a buffer zone of 500 meters was established around each point.This information was combined with the previous two map layers to produce a new map of areas suitable for well sites. Points sources of pollution in the water service area are identified and entered into a GIS.
The map of surficial geology shows the earth materials that lie above bedrock. Since the area under consideration in Connecticut is covered by glacial deposits, the surface consists largely of sand and gravel, with some glacial till and fine-grained sediments. Of these materials, sand and gravel are the most likely to store water that could be tapped with wells. Areas underlain by sand and gravel were selected from the surficial geology map. They were combined with the results of the previous selections to produce a map consisting of: (1) sites in underdeveloped areas underlain by sand and gravel, (2) more than 500 meters from point sources of pollution, and (3) more than 100 meters from unsuitable streams .
A map that shows the thickness of saturated sediments was created by using the GIS to subtract the bedrock elevation from the surface elevation (fig. 17). For this analysis, areas having more than 40 feet of saturated sediments were selected and combined with the previous overlays.
The resulting site selection map shows areas that are undeveloped, are situated outside the buffered pollution areas, and are underlain by 40 feet or more of water-saturated sand and gravel. Because of map resolution and the limits of precision in digitizing, the very small polygons (areas) may not have all of the characteristics analyzed, so another GIS function was used to screen out areas smaller than 10 acres. The final six sites are displayed with the road and stream network and selected place names for use in the field .
Potential water well sites, roads, streams and place names.
The process illustrated by this site selection analysis has been used for many common applications, including transportation planning and waste disposal site location. The technique is particularly useful when several physical factors must be considered and integrated over a large area.

Emergency response planning
The Wasatch Fault zone runs through Salt Lake City along the foot of the Wasatch Mountains in north-central Utah .
A GIS was used to combine road network and earth science information to analyze the effect of an earthquake on the response time of fire and rescue squads. The area covered by the USGS Sugar House 7.5-minute topographic quadrangle map was selected for the study because it includes both undeveloped areas in the mountains and a part of Salt Lake City. Detailed earth science information was available for the entire region.
The road network from a USGS digital line graph includes information on the types of roads, which range from rough trails to divided highways . The locations of fire stations were plotted on the road network. A GIS function called network analysis was used to calculate the time necessary for emergency vehicles to travel from the fire stations to different areas of the city. The network analysis function considers two elements: (1) distance from the fire station, and (2) speed of travel based on the type of road. The analysis shows that under normal conditions, most of the area within the city will be served in less than 7 minutes and 30 seconds because of the distribution and density of fire stations and the continuous network of roads.
The accompanying illustration depicts the blockage of the road network that would result from an earthquake, assuming that any road crossing the fault trace would become impassable. The primary effect on emergency response time would occur in neighborhoods west of the fault trace, where travel times from the fire stations would be noticeably lengthened.
Figure 21. Before faulting. Road network of area covered by the Sugar House quadrangle plotted from USGS digital line graph data, indicating the locations of fire stations and travel times of emergency vehicles. Areas in blue can receive service within 2½minutes, area in green within 5 minutes, areas in yellow within 7½ minutes, and areas in magenta within 10 minutes. Areas in white cannot receive service within 10 minutes.
After faulting, initial model. Network analysis in a GIS produces a map of travel times from the stations after faulting. The fault is in red. Emergency response times have increased for areas west of the fault.
The Salt Lake City area lies on lake sediments of varying thicknesses. These sediments range from clay to sand and gravel, and most are water-saturated. In an earthquake, these materials may momentarily lose their ability to support surface structures, including roads. The potential for this phenomenon, known as liquefaction, is shown in a composite map portraying the inferred relative stability of the land surface during an earthquake. Areas near the fault and underlain by thick, loosely consolidated, water-saturated sediments will suffer the most intense surface motion during an earthquake.Areas on the mountain front with thin surface sediments will experience less additional ground acceleration. The map of liquefaction potential was combined with the road network analysis to show the additional effect of liquefaction on response times.
The final map shows that areas near the fault, as well as those underlain by thick, water-saturated sediments, are subject to more road disruptions and slower emergency response than are other areas of the city.Map of potential ground l liquefaction during an earthquake. The least stable areas are shown by yellows and oranges, the most stable by grays and browns.
Figure 24. After faulting, final model. A map showing the effect of an earthquake on emergency travel times is reduced by combining the liquefaction potential information from figure 23 with the network analysis from .
Three-dimensional GIS
To more realistically analyze the effect of the Earth's terrain, we use three-dimensional models within a GIS. A GIS can display the Earth in realistic, three-dimensional perspective views and animations that convey information more effectively and to wider audiences than traditional, two-dimensional, static maps. The U.S. Forest Service was offered a land swap by a mining company seeking development rights to a mineral deposit in Arizona's Prescott National Forest. Using a GIS, the USGS and the U.S. Forest Service created perspective views of the area to depict the terrain as it would appear after mining .
Figure 25. Prescott National Forest, showing altered topography due to mine development.
To assess the potential hazard of landslides both on land and underwater, the USGS generated a three-dimensional image of the San Francisco Bay area .It created the image by mosaicking eight scenes of natural color composite Landsat 7 enhanced thematic mapper imagery on California fault data using approximately 700 digital elevation models at 1:24,000 scale.
Graphic display techniques
Traditional maps are abstractions of the real world; each map is a sampling of important elements portrayed on a sheet of paper with symbols to represent physical objects. People who use maps must interpret these symbols. Topographic maps show the shape of the land surface with contour lines. Graphic display techniques in GISs make relationships among map elements more visible, heightening one's ability to extract and analyze information.
Two types of data were combined in a GIS to produce a perspective view of a part of San Mateo County, Calif. The digital elevation model, consisting of surface elevations recorded on a 30-meter horizontal grid, shows high elevations as white and low elevations as black (fig. 27). The accompanying Landsat thematic mapper image shows a false-color infrared image of the same area in 30-meter pixels, or picture elements and combine the two images to produce the three- dimentional image.
Maps have traditionally been used to explore the Earth. GIS technology has enhanced the efficiency and analytical power of traditional cartography. As the scientific community recognizes the environmental consequences of human activity, GIS technology is becoming an essential tool in the effort to understand the process of global change. Map and satellite information sources can be combined in models that simulate the interactions of complex natural systems.
Through a process known as visualization, a GIS can be used to produce images— not just maps, but drawings, animations, and other cartographic products. These images allow researchers to view their subjects in ways that they never could before. The images often are helpful in conveying the technical concepts of a GIS to nonscientists.
Adding the element of time
The condition of the Earth's surface, atmosphere, and subsurface can be examined by feeding satellite data into a GIS. GIS technology gives researchers the ability to examine the variations in Earth processes over days, months, and years. As an example, the changes in vegetation vigor through a growing season can be animated to determine when drought was most extensive in a particular region. The resulting normalized vegetation index represents a rough measure of plant health.Working with two variables over time will allow researchers to detect regional differences in the lag between a decline in rainfall and its effect on vegetation. The satellite sensor used in this analysis is the advanced very high resolution radiometer (AVHRR), which detects the amounts of energy reflected from the Earth's surface at a 1-kilometer resolution twice a day. Other sensors provide spatial resolutions of less than 1 meter.
Serving GIS over the Internet
Through Internet map server technology, spatial data can be accessed and analyzed over the Internet. For example, current wildfire perimeters are displayed with a standard web browser, allowing fire managers to better respond to fires while in the field and helping homeowners to take precautionary measures.
The future of GIS
Environmental studies, geography, geology, planning, business marketing, and other disciplines have benefitted from GIS tools and methods. Together with cartography, remote sensing, global positioning systems, photogrammetry, and geography, the GIS has evolved into a discipline with its own research base known as geographic information sciences. An active GIS market has resulted in lower costs and continual improvements in GIS hardware, software, and data. These developments will lead to a much wider application of the technology throughout government, business, and industry.
GIS and related technology will help analyze large datasets, allowing a better understanding of terrestrial processes and human activities to improve economic vitality and environmental quality.

Friday, May 30, 2008

Electromagnetic Spectrum: Distribution of Radiant Energies

Electromagnetic radiation (EMR) extends over a wide range of energies and wavelengths (frequencies). A narrow range of EMR extending from 0.4 to 0.7 µm, the interval detected by the human eye, is known as the visible region (also referred to as light but physicists often use that term to include radiation beyond the visible). White light contains a mix of all wavelengths in the visible region. It was Sir Isaac Newton who first in 1666 carried out an experiment that showed visible light to be a continuous sequence of wavelengths that represented the different color the eye can see. He passed white light through a glass prism and got this result:

The principle supporting this result is that as radiation passes from one medium to another, it is bent according to a number called the index of refraction. This index is dependent on wavelength, so that the angle of bending varies systematically from red (longer wavelength; lower frequency) to blue (shorter wavelength; higher frequency). The process of separating the constituent colors in white light is known as dispersion. These phenomena also apply to radiation of wavelengths outside the visible (e.g., a crystal's atomic lattice serves as a diffraction device that bends x-rays in different directions).

The distribution of the continuum of all radiant energies can be plotted either as a function of wavelength or of frequency in a chart known as the electromagnetic (EM) spectrum. Using spectroscopes and other radiation detection instruments, over the years scientists have arbitrarily divided the EM spectrum into regions or intervals and applied descriptive names to them.The EM spectrum, plotted here in terms of wavelengths, is shown here.

Beneath is a composite illustration taken from the Landsat Tutorial Workbook (credited there to Lintz and Simonett, Remote Sensing of the Environment, who identify it as a modification of an earlier diagram by Robt. Colwell) that shows in its upper diagram the named spectral regions in terms of wavelength and frequency and in the lower diagram the physical phenomena that give rise to these radiation types and the instruments (sensors) used to detect the radiation. (Although the width of this second diagram scales closely to the width of the spectrum chart above it, the writer experienced difficulty in centering this second diagram on the present page; it needs some leftward offset so that the narrow pair of vertical lines coincides with the visible range in the upper diagram.)

Although it is somewhat redundant, we reproduce here still another plot of the EM Spectrum, with added items that are self-explanatory:

Colors in visible light are familiar to most, but the wavelength limits for each major color are probably not known to most readers. Here is a diagram that specifies these limits (the purple on the far left is in the non-visible ultraviolet; the deep red on the far right is the beginning of the infrared). The human eye is said to be able to distinguish thousands of slightly different colors (one estimate placed this at distinguishable 20000 color tints).

Different names for (wave)length units within intervals (those specified by types) that subdivide the EM spectrum, and based on the metric system, have been adopted by physicists as shown in this table:

(Both in this Tutorial and in other texts, just which units are chosen can be somewhat arbitrary, i.e., the authors may elect to use micrometers or nanometers for a spectral location in the visible. Thus, as an example, 5000 Angstroms, 500 nanometers, and 0.5 micrometers all refer to the same specific wavelength; see next paragraph.)

At the very energetic (high frequency and short wavelength) end are gamma rays and x-rays (whose wavelengths are normally measured in angstroms [Å], which in the metric scale are in units of 10-8 cm). Radiation in the ultraviolet extends from about 300 Å to about 4000 Å. It is convenient to measure the mid-regions of the spectrum in one of two units: micrometers (µm), which are multiples of 10-6 m or nanometers (nm), based on 10-9 m. The visible region occupies the range between 0.4 and 0.7 µm, or its equivalents of 4000 to 7000 Å or 400 to 700 NM The infrared region, spanning between 0.7 and 1000 µm (or 1 mm), has four subintervals of special interest: (1) reflected IR (0.7 - 3.0 µm), and (2) its film responsive subset, the photographic IR (0.7 - 0.9 µm); (3) and (4) thermal bands at (3 - 5 µm) and (8 - 14 µm). We measure longer wavelength intervals in units ranging from mm to cm. to meters. The microwave region spreads across 0.1 to 100 cm, which includes all of the interval used by radar systems. These systems generate their own active radiation and direct it towards targets of interest. The lowest frequency-longest wavelength region beyond 100 cm is the realm of radio bands, from VHF (very high frequency) to ELF (extremely low frequency); units applied to this region is often stated as frequencies in units of Hertz (1 Hz = 1 cycle per second; KHz, MHz and GHz are kilo-, mega-, and giga- Hertz respectively). Within any region, a collection of continuous wavelengths can be partioned into discrete intervals called bands.

Referring to the Phenomenology diagram (fourth illustration above): That chart indicates many of the atomic or molecular mechanisms for forming these different types of radiation; it also depicts the spectral ranges covered by many of the detector systems in common use. This diagram indicates that electromagnetic radiation is produced in a variety of ways. Most involve actions within the electronic structure of atoms or in movements of atoms within molecular structures (as affected by the type of bonding). One common mechanism is to excite an atom by heating or by electron bombardment which causes electrons in specific orbital shells to momentarily move to higher energy levels; upon dropping back to the original shell the energy gained is emitted as radiation of discrete wavelengths. At high energies even the atom itself can be dissociated, releasing photons of short wavelengths. And photons themselves, in an irradiation mode, are capable of causing atomic or molecular responses in target materials that generate emitted photons (in the reflected light process, the incoming photons that produce the response are not necessarily the same photons that leave the target).

Most remote sensing is conducted above the Earth either within or above the atmosphere. The gases in the atmosphere interact with solar irradiation and with radiation from the Earth's surface. The atmosphere itself is excited by EMR so as to become another source of released photons. Here is a generalized diagram showing relative atmospheric radiation transmission of different wavelengths.

Blue zones (absorption bands) mark minimal passage of incoming and/or outgoing radiation, whereas, white areas (transmission peaks) denote atmospheric windows, in which the radiation doesn't interact much with air molecules and hence, isn't absorbed. This next plot, made with the AVIRIS hyperspectral spectrometer (see page page 13-9), gives more a more detailed spectrum, made in the field looking up into the atmosphere, for the interval 0.4 to 2.5 µm (converted in the diagram to 400-2500 nanometers).

Most remote sensing instruments on air or space platforms operate in one or more of these windows by making their measurements with detectors tuned to specific frequencies (wavelengths) that pass through the atmosphere. However, some sensors, especially those on meteorological satellites, directly measure absorption phenomena, such as those associated with carbon dioxide, CO2 and other gaseous molecules. Note in the second diagram above that the atmosphere is nearly opaque to EM radiation in part of the mid-IR and almost all of the far-IR region (20 to 1000 µm). In the microwave region, by contrast, most of this radiation moves through unimpeded, so radar waves reach the surface (although raindrops cause backscattering that allows them to be detected). Fortunately, absorption and other interactions occur over many of the shorter wavelength regions, so that only a fraction of the incoming radiation reaches the surface; thus harmful cosmic rays and ultraviolet (UV) radiation that could inhibit or destroy certain life forms are largely prevented from hitting surface environments.

I-10: From the first atmospheric absorption figure, list the four principal windows (by wavelength interval) open to effective remote sensing from above the atmosphere.

Backscattering (scattering of photons in all directions above the target in the hemisphere that lies on the source side) is a major phenomenon in the atmosphere. Mie scattering refers to reflection and refraction of radiation by atmospheric constituents (e.g., smoke) whose dimensions are of the order of the radiation wavelengths. Rayleigh scattering results from constituents (e.g., molecular gases [O2, N2 {and other nitrogen compounds}, and CO2], and water vapor) that are much smaller than the radiation wavelengths. Rayleigh scattering increases with decreasing (shorter) wavelengths, causing the preferential scattering of blue light (blue sky effect); however, the red sky tones at sunset and sunrise result from significant absorption of shorter wavelength visible light owing to greater "depth" of the atmospheric path as the Sun is near the horizon. Particles much larger than the irradiation wavelengths give rise to nonselective (wavelength-independent) scattering. Atmospheric backscatter can, under certain conditions, account for 80 to 90% of the radiant flux observed by a spacecraft sensor.

Remote sensing of the Earth traditionally has used reflected energy in the visible and infrared and emitted energy in the thermal infrared and microwave regions to gather radiation that can be analyzed numerically or used to generate images whose tonal variations represent different intensities of photons associated with a range of wavelengths that are received at the sensor. This sampling of a (continuous or discontinuous) range(s) of wavelengths is the essence of what is usually termed multispectral remote sensing.

Images made from the varying wavelength/intensity signals coming from different parts of a scene will show variations in gray tones in black and white versions or colors (in terms of hue, saturation, and intensity in colored versions). Pictorial (image) representation of target objects and features in different spectral regions, usually using different sensors (commonly with bandpass filters) each tuned to accept and process the wave frequencies (wavelengths) that characterize a given region, will normally show significant differences in the distribution (patterns) of color or gray tones. It is this variation which gives rise to an image or picture. Each spectral band will produce an image which has a range of tones or colors characteristic of the spectral responses of the various objects in the scene; images made from different spectral bands show different tones or colors.

This point - that each spectral band image is unique and characteristic of its spectral makeup - can be dramatically illustrated with views of astronomical bodies viewed through telescopes (some on space platforms) equipped with different multispectral sensing devices. Below are four views of the nearby Crab Nebula, which is now in a state of chaotic expansion after a supernova explosion first sighted in 1054 A.D. by Chinese astronomers (see Section 20 - Cosmology - for other examples). The upper left illustration shows the Nebula as sensed in the high energy x-ray region; the upper right is a visual image; the lower left was acquired from the infrared region; and the lower right is a long wavelength radio telescope image.

By sampling the radiation coming from any material or class under observation over a range of continuous (or intermittent, in bands) spectral interval, and measuring the intensity of reflectance or emittance for the different wavelengths involve, a plot of this variation forms what is referred to as a spectral signature, the subject of the next page's discussion.

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The Concept of Remote Sensing

If you have heard the term "remote sensing" before you may have asked, "what does it mean?" It's a rather simple, familiar activity that we all do as a matter of daily life, but that gets complicated when we increase the scale at which we observe. As you view the screen of your computer monitor, you are actively engaged in remote sensing.

A physical quantity (light) emanates from that screen, whose imaging electronics provides a source of radiation. The radiated light passes over a distance, and thus is "remote" to some extent, until it encounters and is captured by a sensor (your eyes). Each eye sends a signal to a processor (your brain) which records the data and interprets this into information. Several of the human senses gather their awareness of the external world almost entirely by perceiving a variety of signals, either emitted or reflected, actively or passively, from objects that transmit this information in waves or pulses. Thus, one hears disturbances in the atmosphere carried as sound waves, experiences sensations such as heat (either through direct contact or as radiant energy), reacts to chemical signals from food through taste and smell, is cognizant of certain material properties such as roughness through touch (not remote), and recognizes shapes, colors, and relative positions of exterior objects and classes of materials by means of seeing visible light issuing from them. In the previous sentence, all sensations that are not received through direct contact are remotely sensed.

I-1 In the illustration above, the man is using his personal visual remote sensing device to view the scene before him. Do you know how the human eye acts to form images? If not, check the answer. ANSWER

However, in practice we do not usually think of our bodily senses as engaged in remote sensing in the way most people employ that term technically. A formal and comprehensive definition of applied remote sensing * is:

Remote Sensing in the most generally accepted meaning refers to instrument-based techniques employed in the acquisition and measurement of spatially organized (most commonly, geographically distributed) data/information on some property(ies) (spectral; spatial; physical) of an array of target points (pixels) within the sensed scene that correspond to features, objects, and materials, doing this by applying one or more recording devices not in physical, intimate contact with the item(s) under surveillance (thus at a finite distance from the observed target, in which the spatial arrangement is preserved); techniques involve amassing knowledge pertinent to the sensed scene (target) by utilizing electromagnetic radiation, force fields, or acoustic energy sensed by recording cameras, radiometers and scanners, lasers, radio frequency receivers, radar systems, sonar, thermal devices, sound detectors, seismographs, magnetometers, gravimeters, scintillometers, and other instruments.

I-2 To help remember the principal ideas within this definition, make a list of key words in it. ANSWER

This is a rather lengthy and all-inclusive definition. Perhaps two more simplified definitions are in order: The first, more general, includes in the term this idea: Remote Sensing involves gathering data and information about the physical "world" by detecting and measuring signals composed of radiation, particles, and fields emanating from objects located beyond the immediate vicinity of the sensor device(s). The second is more restricted but is pertinent to most of the subject matter of this Tutorial: In its common or normal usage (by tacit implication), Remote Sensing is a technology for sampling electromagnetic radiation to acquire and interpret non-contiguous geospatial data from which to extract information about features, objects, and classes on the Earth's land surface, oceans, and atmosphere (and, where applicable, on the exteriors of other bodies in the solar system, or, in the broadest framework, celestial bodies such as stars and galaxies).

 What is the meaning of "geospatial"? Are there any differences in meaning of the terms "features", "objects", and "classes"?

 Applied Remote Sensing involves the detecting and measuring of electromagnetic energy (usually photons) emanating from distant objects made of various materials, so that the user can identify and categorize these objects - usually, as rendered into images - by class or type, substance, and spatial distribution. Generally, this more conventional description of remote sensing has a specific criterion by which its products point to this specific use of the term: images much like photos are a main output of the sensed surfaces of the objects of interest. However, the data often can also be shown as "maps" and "graphs", or to a lesser extent, as digital numbers that can be input to computer-based analysis, and in this regard are like the common data displays resulting from geophysical remote sensing. As applied to meteorological remote sensing, both images (e.g., clouds) and maps (e.g., temperature variations) can result; atmospheric studies (especially of the gases in the air, and their properties) can be claimed by both traditionalists and geophysicists.

All of these statements are valid and, taken together, should give you a reasonable insight into the meaning and use of the term "Remote Sensing" but its precise meaning depends on the context in which it is spoken of.

Thus, as the above comments suggest, some technical purists arbitrarily stretch the scope or sphere of remote sensing to include other measurements of physical properties from sources "at a distance" that are more properly included in the general term "Geophysics". (Geophysics has a scientific connotation: it is pertinent to the study of the physical properties of Earth and other planets. It likewise has an applied connotation: it is the technology often used to search for oil and gas and for mineral deposits.) This latter is especially conducted through such geophysical methods as seismic, magnetic, gravitational, acoustical, and nuclear decay radiation surveys. Magnetic and gravitational measurements respond to variations in force fields, so these can be carried out from satellites. Remote sensing, as defined in this context, would be a subset within the branch of science known as Geophysics. However, practitioners of remote sensing, in its narrower meaning, tend to exclude these other areas of Geophysics from their understanding of the meaning implicit in the term.

Still, space systems - mostly on satellites - have made enormous contributions to regional and global geophysical surveys. This is because it is very difficult and costly to conduct ground and aerial surveys over large areas and then to coordinate the individual surveys by joining them together. To obtain coherent gravity and magnetic data sets on a world scale, operating from the global perspective afforded by orbiting satellites is the only reasonable alternate way to provide total coverage.

One could argue that Geophysics deserves a Section of its own but in the remainder of this Tutorial we choose to confine our attention almost entirely to those systems that produce data by measuring in the electromagnetic radiation (EMR) spectrum (principally in the Visible, Infrared, and Radio regions). We will reserve our treatment of Geophysics to three pages near the end of this Introduction. There you are given examples of the use of satellite instruments to obtain information on particles and fields as measured inside and around the Earth; in Sections 19 and 20 (Planets and Cosmology) there will also be some illustrations of several types of geophysical measurements.

One mode of remote sensing not treated in the Tutorial is acoustic monitoring of sound waves in atmospheric and marine environments. For example, volcanic eruptions or nuclear (testing) explosions can be detected by sensitive sound detectors. Sonar is used to track submarines and surface ships in the oceans. Sound through water are also involved in listening to marine animals such as whales and porpoises.

It may seem surprising to realize that going to the doctor can involve remote sensing. Most obvious, on a miniature scale, is listening to a heartbeat using the stethoscope. But in the field of modern medical technology, powerful, often large, instruments such as CATscans and Magnetic Resonance Imaging, are now almost routinely used for non-invasive subskin investigation of human tissue and organs. This is indeed another major application of remote sensing that will be surveyed on pages I-26c through I-26e.

The traditional way to start consideration of what remote sensing is and means is to set forth its underlying principles in a chapter devoted to the Physics on which remote sensing is founded. This will be done in the next 5 pages. The ideas developed may seem arcane. These pages contain the "technical jargon" that remote sensing specialists like to banty about. With this caveat in mind, work through the pages, try to understand the esoteric, and commit to memory what seems useful.

* The term "remote sensing" is itself a relatively new addition to the technical lexicon. It was coined by Ms Evelyn Pruitt in the mid-1950's when she, a geographer/oceanographer, was with the U.S. Office of Naval Research (ONR) outside Washington, D.C.. It seems to have been devised by Ms Pruitt to take into account the new views from space obtained by the early meteorological satellites which were obviously more "remote" from their targets than the airplanes that up until then provided mainly aerial photos as the medium for recording images of the Earth's surface. No specific publication or professional meeting where the first use of the term occurred is cited in literature consulted by the writer (NMS). Those "in the know" claim that it was verbally used openly by the time of several ONR-sponsored symposia in the 1950s at the University of Michigan. The writer believes he first heard this term at a Short Course on Photogeology coordinated by Dr. Robert Reeves at the Annual Meeting of the Geological Society of America in 1958.


Alpine Biome

Cold, snowy, windy. When you hear those words they make you think of mountains. The Alpine biome is like winter is to people in New England; snow, high winds, ice, all the typical winter things. In Latin the word for 'high mountain' is 'alpes'. That is where today's word alpine comes from.

Alpine biomes are found in the mountain regions all around the world. They are usually at an altitude of about 10,000 feet or more. The Alpine biome lies just below the snow line of a mountain. As you go up a mountain, you will travel through many biomes. In the North American Rocky Mountains you begin in a desert biome. As you climb you go through a deciduous forest biome, grassland biome, steppe biome, and taiga biome before you reach the cold Alpine biome.

In the summer average temperatures range from 10 to 15° C . In the winter the temperatures are below freezing. The winter season can last from October to May. The summer season may last from June to September. The temperatures in the Alpine biome can also change from warm to freezing in one day.

Because the severe climate of the Alpine biome, plants and animals have developed adaptations to those conditions. There are only about 200 species of Alpine plants. At high altitudes there is very little CO2, which plants need to carry on photosynthesis. Because of the cold and wind, most plants are small perennial groundcover plants which grow and reproduce slowly. They protect themselves from the cold and wind by hugging the ground. Taller plants or trees would soon get blown over and freeze. When plants die they don't decompose very quickly because of the cold. This makes for poor soil conditions. Most Alpine plants can grow in sandy and rocky soil. Plants have also adapted to the dry conditions of the Alpine biome. Plant books and catalogs warn you about over watering Alpine plants.

Alpine animals have to deal with two types of problems: the cold and too much high UV wavelengths. This is because there is less atmosphere to filter UV rays from the sun. There are only warm blooded animals in the Alpine biome, although there are insects. Alpine animals adapt to the cold by hibernating, migrating to lower, warmer areas, or insulating their bodies with layers of fat. Animals will also tend to have shorter legs, tails, and ears, in order to reduce heat loss. Alpine animals also have larger lungs, more blood cells and hemoglobin because of the increase of pressure and lack of oxygen at higher altitudes. This is also true for people who have lived on mountains for a long time, like the Indians of the Andes Mountains in South America and the Sherpas of the Himalayas in Asia.
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Job Location(s):
Queensland - Brisbane

Surveyors - This role is perfectly suited for graduates and students with 1 to 5 years experience looking for career direction, development and advancement. As part of our young and energetic team, you will have the opportunity to work on a variety of challenging projects, whilst being well rewarded for your efforts.

Senior Surveyors - Opportunities are also available for highly competent and professional Senior Surveyors to assist in developing our business. You will be responsible for project management, communication across departments, assisting with budgets and client relationship management.

A wide variety of projects, including Cadastral (Rural / Urban), Engineering, Subdivisions, GPS Surveys, Community Title, Topographic, Infrastructure & Mixed Use Development are available in a range of locations throughout Queensland, in addition to our Brisbane head office.

For further information, visit our website or contact our Recruitment Specialist Sue Moseman on +61 7 3124 9565. To register your interest in this position, send your application to quoting reference CA42.
Additional Information
Position Type: Full Time, Employee
Job Starting Date: May 29, 2008
Job Closing Date: June 30, 2008
As part of our Award Winning staff benefits scheme, our people enjoy the following benefits:
• Vibrant social club
• Attractive salary packages and flexible work options
• Opportunity for career progression, training and skill development
• Mentoring by industry leaders within our experienced team
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• Opportunity to work closely with our team of professional planners, urban designers and project managers

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Fortitude Valley, 4006
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Phone Number: +61 7 3124 9500
click here to apply online

Thursday, May 29, 2008

Geothermal Energy

Geothermal energy – literally heat from the earth – is a clean and versatile natural resource for the world’s steadily increasing energy needs.
When the rising hot water and steam is trapped in permeable and porous rocks under a layer of impermeable rock, it can form a geothermal reservoir.
Earth’s natural geologic processes, such as those associated with geysers and hot springs, allow magma to rise relatively close to the earth’s surface. In places like the “Pacific Ring of Fire,” the magma heats vast regions of underground rock located high above the magma chambers. Often porous and fractured, the hot rock can become saturated with rainwater that has seeped underground, creating geothermal reservoirs of hot water and steam. Geothermal reservoirs vary in temperature – sometimes reaching as high as 700°F (371°C).

Geothermal heat and geothermal reservoirs are generally referred to as geothermal resources and are located in many parts of the world. In the United States, they occur primarily in the western states including California.
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New map shows fire scars at different areas across world

Map shows global vegetation over an area equivalent to the EU27 burns every year23 May 2008
A University of Leicester geographer has come up with a map that shows that about 3.5 to 4.5 million square km of the global vegetation burns every year, an area which is equivalent to the European Union (EU27) and larger than India.
The map produced by Dr Kevin Tansey, a leading scientist in the Department of Geography, shows a visual impression of the fire scars on our planet between 2000 and 2007.
We have produced, for the first time, a global database and map of the occurrence of fire scars covering the period 2000-2007. Prior to this development, data were only available for the year 2000. With seven years of data, it is not possible to determine if there is an increasing trends in the occurrence of fire, but we have significant year-to-year differences, of the order of 20 per cent, in the area that is burnt, said Dr Tansey, a Lecturer in Remote Sensing.
Funded by the Joint Research Centre of the European Commission, the map provides information that may be vital for scientists and agencies involved in monitoring global warming, measuring and understanding pollutants in the atmosphere, managing forest and controlling fire, and even for predicting future fire occurrence.
This unique data set is in much demand by a large community of scientists interested in climate change, vegetation monitoring, atmospheric chemistry and carbon storage and flows, Tansey said.
As to how the information necessary for creating this map was collected, Tansey said: We have used the VEGETATION instrument onboard the SPOT European satellite, which collects reflected solar energy from the Earths surface, providing global coverage on almost a daily basis.
The researchers added: When vegetation burns the amount of reflected energy is altered, long enough for us to make an observation of the fire scar. Supercomputers located in Belgium were used to process the vast amounts of satellite data used in the project. At the moment, we have users working towards predicting future fire occurrence and fire management issues in the Kruger Park in southern Africa.
Tansey also revealed those parts of the planet where the majority of fires occur.
The majority of fires occur in Africa. Large swathes of savannah grasslands are cleared every year, up to seven times burnt in the period 2000-2007. The system is sustainable because the grass regenerates very quickly during the wet season. From a carbon perspective, there is a net balance due to the regenerating vegetation acting as a carbon sink. Fires in forests are more important as the affected area becomes a carbon source for a number of years, he said.
The forest fires last summer in Greece and in Portugal a couple of years back, remind us that we need to understand the impact of fire on the environment and climate to manage the vegetation of the planet more effectively. Probably 95 per cent of all vegetation fires have a human source; crop stubble burning, forest clearance, hunting, arson are all causes of fire across the globe. Fire has been a feature of the planet in the past and under a scenario of a warmer environment will certainly be a feature in the future, he added.

Source :

Wednesday, May 28, 2008

Origins of the Gurjars

The origins of the Gurjars are uncertain. The Gurjara clan appeared in northern India about the time of the Huna invasions of northern India. Some scholars, such as V. A. Smith, believed that the Gujjars were foreign immigrants, possibly a branch of Hephthalites (”White Huns”). D. B. Bhandarkar (1875-1950) believed that Gujars came into India with the Hunas, and the name of the tribe was sanskritized to “Gurjara”. He also believed that several places in Central Asia, such as “Gurjistan”, are named after the Gujars and that the reminiscences of Gujar migration is preserved in these names. General Cunningham identified the Gujjars with Yuezhi or Tocharians.
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Perth as seen from space

NEW images released by Landgate's Satellite Remote Sensing Services show Perth and WA with stunning clarity.

Landgate chief executive Grahame Searle said many West Australians were unaware of the ground-breaking advances taking place in satellite imagery.

"SRSS images and data are not only spectacular to view but assist in all facets of everyday life, from fighting fires to planning crops and catching fish,'' Mr Searle said.

The Perth public can get an ``astronaut's view'' of the city at a Landgate open day next Saturday from 10am-4pm at 65 Brockway Rd in Floreat.

Copies of satellite images showing suburbs, streets and even houses will be available.

Source :

Tuesday, May 27, 2008

Italian Satellites Monitor Earthquake Damages In Sichuan


 COSMO-SkyMed, the Italian satellite system for Earth observation, is being used to help the Chinese areas hit by the devastating earthquake of May 12. Yesterday, by request of the Chinese Government, the ASI satellites captured two images of the area surrounding the city of Guan Xian, close to the epicentre, thus proving to be able to operate on critical areas with very short response time.

Moreover, due to the difficult weather conditions, only the Italian radar satellites could operate yesterday on Sichuan. The picture clearly shows a dam, that will be constantly monitored in the next days for damages.

The images were processed at ASI's Data Acquisition Centre in Matera, southern Italy, managed for ASI by Telespazio.

In the next few days, COSMO-SkyMed will continue providing useful data to the Chinese Gonvernment, to the Italian Civilian Protection Department (which is planning a mission in Sichuan) and to various NGOs. COSMO images will be used to detect damages to buildings and metal structures, including bridges and dams.

COSMO-SKyMed is a satellite system for Earth observation by the Italian Space Agency and the Italian Defence Ministry. Telespazio (a Thales/Finmeccanica company) manages the ground segment, while the satelliets are built by Thales Alenia Space Italia. Once completed, the system will be made of four satellites, two of which are already in orbit and operational.

Source :

Rs 3 million research project on bats approved in Pakistan

 Lahore - THE Higher Education Commission (HEC) had approved a research project of the University of Veterinary and Animal Sciences (UVAS), titled “Diversity and Conservation Biology of Bats in Selected Protected Areas of Pakistan.”

According to a press statement, the Department of Wildlife and Ecology of the UVAS will execute this research project, the will cost Rs 3.177 million and will be completed in three years.

Department of Wildlife and Ecology Chairman Dr Muhammad Mehmood-ul-Hassan is the Principal Investigator of the project.

The project aims to assess population status and diversity of the bat fauna of Pakistan using cutting-edge technologies like bat bioacoustics, mitochondrial DNA and to analyse and compare temporal and spatial variations in the composition of bat groupings at the same and different habitats.

The university will prepare distribution maps of each species using Geographic Information System (GIS) and Global Positioning System (GPS) in order to refine geospatial distribution and habitat preferences of various bat species of the study areas.

Under the project, the Department of Wildlife of the UVAS will produce trained manpower through its MPhil and PhD degree programmes for the study and conservation of biodiversity in Pakistan.

These studies will mainly be conducted in Margalla Hills National Park Islamabad, Chinji National Park Khushab and Lal Suhanra National Park Bahawalpur and in some cropped and non-cropped areas of Pakistan.

According to Dr Mehmood-ul-Hassan, bats are found almost everywhere in Pakistan and are important for the maintenance of a healthy ecosystem, but they are seen with mild disdain to revulsion by the general public.

“Fruit bats are important pollinators and seeds dispersers. Insectivorous bats consume millions of insects, which would otherwise destroy valuable crops or spread diseases,” he said.

He added that bats were rarely considered in either environmental policies or educational projects and as a result, Pakistan was unable to meet its commitment to the Convention on Biological Diversity (CBD), of which it is a signatory.

Since there has been no long term field study on any bat species, Dr Mehmood said the proposed project would provide baseline information on the biodiversity of the country’s poorly-known bat fauna.

While policies governing the management of biodiversity are in place, the paucity of scientific information on the bats and lack of staff trained in wildlife science are impediments to effective conservation of natural resources.

“This project is designed to cover both these aspects,” Dr Mehmood added.

Source :


 Senior GIS Engineer / Project Lead (GIS) - (GE Small World Magik

Job Description
Candidate should have extensive experience in magik
Able to work on FME (feature Manipulation Engine) Environment
able to understand the Existing Data model, Able to create
joins and able to assist to other software programmers on Small
behavior and should have Extensive knowledge on case Tool.
Should have good Knowledge on Data Migration using the FME and
to create own magik code on FME Environment.
Should have good knowledge on trace back error and bug fixing
the migration. Having telecom data model knowledge will be

Experience/Skill Set
B.E. / B.Tech / M.Sc / M.Tech (Remote Sensing/ Geology/ Geometrics)
with 4
- 8 years of work experience.

Sr. GIS Engineer

Job Description
The person would be responsible for end to end for short duration
data creation projects, day to day production data, ensuring quality
data being produced by the team. He/she will have to invoke suitable
quality control measures/initiative s, technical trouble shooting,
innovation, automation and technical support to client/sales etc. and
expected to complement project execution with hands on production
and final
processing to achieve both timely and quality data.
The person should have exposure in Image processing software like
3.x, ArcInfo W/S, AutoCAD and MapInfo is very much required,
experience in
project execution of teams of size 4 to 10, creation of geographic
(DEM, Land Use etc.) sets is essential.
Good technical knowledge on GIS processing. Experience with
software's like
ERDAS, ENVI and ArcGIS and Global Mapper and Good technical
knowledge on
satellite imaging and processing front is required.

Experience/Skill Set
B.E. / B.Tech / M.Sc / M.Tech (Remote Sensing/ Geology/ Geometrics)
with 4
- 6 years of work experience.

The person should be Quality orientation, Logical/analytical thinking
ability, Positive attitude , Inquisitiveness for any new knowledge
Passion and Commitment to the Remote Sensing domain (Land Use), Good
communication (verbal and written) and presentation skills


Sent your cv on msharma@bluekans. com

Origin of Gurjars

The fictitious myth about Gurjars is that they are foreigner. Many historians say that Gurjar come to India along with Huns in the 5th century and with the help of Brahmins, they prove themselves as khsatriya.

Britishers and 19th century historians firstly wrote Indian history in a systematic manner, they tried to prove that the Gurjars migrated from central Asia in the 5th century. Following there words Indian historian also writes that, Gurjar were invaders from Central Asia. They also state that not only Gurjar but also complete Aryan race is immigrated to India.

On the other hand, how our historians has forgotten that, complete central Asia and subcontinent belongs to Indian boundaries in history. Caspian Sea is on the name of Aryan king Kashyap, Mansarovar now in China is on the name of Suryavansi King Mannu. Modern research have proved that home of Aryans was India, Pakistan, Afghanistan, Iran, black sea in the west, and great wall of China in the East, covering the whole central Asia.

The believer of the myth, that Gurjars are foreigners, like Sir James Campbell, General Crook, Colonel Todd, Mr. forbs, Dr. Bhagwan Lal Inder Ji and all other have agree that present Kasana gotra of Gurjars are successors of great Kushans.

Not only Kushans but there were also great kings in the present Indian history before 5th century. In the book (Bhartiya kala avom sanskriti ka itihas) Dr. Bhagwat Sharan Upadhyaya agrees that at 150 B.C. Gurjars were in Kabul and Punjab. General Kernighan has stated the same in 100 B.C. Even in Brahmi Script, it has stated that Gurjars ruled the western India.

If Gurjar were foreigner then, how they assumed as khsatriya, as it has stated on the various pillars inscription of the different Gurjar kingdoms that, they are the successors of great Ragukulvanshi and Suryavanshi. In the ancient history’s Maha Kavi BalShekar’s “Balbahrat prachand pandav granth” and Great Mihir Bhoj Partihar’s “Sagar Taal Prashti”, it has mentioned that Gurjars are Suryavanshi and they are the successors of great Raghukul (successors of Ikshvaku, Prthu, Harischandra, Ragu, and Dasrath). In Markandai Puran and Panchtantra, there is a reference of the Gurjar tribe. Moreover, the word Gurutar (Gurjar) has mentioned in the epic Ramayana for Maharaja Dasrath.

ISRO aggressively promoting commercial launches: ISRO chief GM Nair

27 May 2008
India - Bouyed with the high success rate achieved with its commercial launches, the Indian Space Research Organisation (ISRO) has said it plans to step up its commercial activities in order to earn larger revenues. It says it is also negotiating with certain countries that restrict the use of Indian launch vehicles.
''Our domestic requirement is four to five launches per year and we are trying to increase commercial launches. We are favourably placed since our costs are about 80% of international launching costs. But some countries have restrictions on launching their satellites from other countries, as well as Indian launch vehicles. The technology which we use is applicable for dual purpose - hence some of these countries have reservations,'' ISRO chairman, G Madhavan Nair, said.
His reference to dual use refers to launching satellites for military as well as civilian purposes.
Nair was talking to reporters after receiving the Ramomohan Puraskar 2008 in Kolkata last week.
ISRO launched the PSLV C-9 last month with two satellites Cartosat-2A and the IMS-1, along with eight nano-satellites. It became only the second country in the world after Russia, to launch multi-satellites with polar satellite launch vehicles.
Talking about preparations related to the launch of the country's moon mission, Chandrayan-1, India's first unmanned mission to the moon, he said that it was proceeding on schedule and that the launch was expected in the third quarter of the year.
He also said that the satellite would be programmed to orbit the moon for two years. During its orbit, the Chandrayaan will take pictures of the lunar surface in phases and also look for the existence of water and special elements like helium-3.
After the launch of the Chandrayan-1, ISRO will turn its attention to the launch of the Geosynchronous Satellite Launch Vehicle (GSLV).
He also added that work was on to shift ISRO's remote sensing application centre from Kharagpur to Kolkata and it will be operational towards the end of next year.

Source :

Remote Sensing training centre in Kolkata soon

Centre is going to open by the next year - ISRO

A remote sensing application-training centre is scheduled to come up in the city by the next year, said G. Madhavan Nair, Chairman of the Indian Space Research Organisation (ISRO), at a function here on Thursday. “Work on the project has already started at the Salt Lake City site provided by the State government,” he said.
Expressing satisfaction about the success of the recent Polar Satellite Launch Vehicle (PSLV) launch at Sriharikota, he said, “Images better than the Google Earth will be available through the satellites in another six months.”
Speaking about the future projects of ISRO, Dr. Nair said, “the unmanned Chandrayaan lunar vehicle is in its building and testing phase and is expected to be launched by the third quarter of this year.”
The mission will study the lunar surface nature and probe the availability of water and helium on the moon. Dr. Nair said ISRO is also launching an indigenous cryogenic flight, by the end of this year, using a Geo-synchronic Satellite Launch Vehicle (GSLV). “Our organisation will also launch two commercial satellites for the European Union within this year,” he said.
Dr. Nair said policy restrictions of some foreign countries were hindering more commercial satellite launches which are only 14 as opposed to 50 indigenous launches so far. “We are in talks with various international agencies to smoothen the process,” he said.

Source :

Jason-2 Satellite Data to Help NOAA Track Global Sea Level

A new satellite set to launch next month will monitor the rate of sea-level rise and help measure the strength of hurricanes, according to a leading NOAA scientist.

At a press briefing today, Laury Miller, chief of NOAA’s Laboratory for Satellite Altimetry, said NOAA will use data from the Jason-2/Ocean Surface Topography Mission (OSTM) to extend a 15-year record from two earlier altimeter missions that currently show sea level is rising at a rate of 3.2 mm/year — nearly twice as fast as the previous 100 years. “This rate, if it continues unchanged over the coming decades, will have a large impact on coastal regions, in terms of erosion and flooding,” said Miller.

The Jason-2/OSTM is scheduled for lift off June 15 at 1:47 a.m. from Vandenberg Air Force Base, Calif. The spacecraft is a joint, international effort between NOAA, NASA, France’s Centre National d’Etudes Spatiales (CNES), and the European Organisation for the Exploitation of Meteorological Satellites (Eumetsat).

Like its predecessor missions TOPEX/Poseidon and Jason-1, Jason-2/OSTM is designed to extend the climate data record by providing a long-term survey of Earth’s oceans, tracking ocean circulation patterns and measuring sea-surface heights and the rate of sea-level rise. These are all key factors in understanding climate change.

The satellite will use a radar altimeter instrument attached to it and fly in a low Earth orbit allowing it to monitor 95 percent of Earth’s ice-free oceans every 10 days.

In addition to detecting climate change factors, Jason-2/OSTM will also be used in the prediction of short-term, severe weather events, such as hurricanes and tropical storms. According to Miller, NOAA will use the altimeter measurements to monitor ocean conditions that trigger changes in the strength of tropical cyclones, as they move over the ocean towards the land. The technique involves mapping the ocean heat content — the fuel that feeds a storm’s intensity — along the storm’s predicted track.

“Using data received in earlier altimeter missions during hurricanes with wind speeds in excess of 155 miles per hour, we’ve been able to reduce our intensity prediction error by an average of five percent – and in some cases as much as 20 percent,” Miller said. “If we increase the accuracy of intensity predictions, we help save lives.”

During the Jason-2/OSTM lifespan, NOAA will work with CNES to handle the complete ground system support. This includes commanding all the satellite’s maneuvers, downloading all the data the satellite captures, and distributing it to weather and climate forecasters, who are monitoring ocean-born storms and phenomena such as El Niño/La Niña and global sea-level rise.

Additionally, Jason-2/OSTM will be the first, newly launched satellite in which NOAA provides ground support from its NOAA Satellite Operations Facility in Suitland, Md. The facility opened in 2007 and houses $50 million worth of high-tech equipment and controls nearly $5 billion in satellites.

“NOAA is definitely up to the challenge of providing smooth, continuous operational support for this mission, which is sure to bring tangible benefits throughout the world,” said Mike Mignogno, program manager for NOAA’s Polar-orbiting Operational Environmental Satellites.

Source :

Monday, May 26, 2008

Images Better than Google:India plans to launch satellite mapping service on website

The Indian Space Research Organization (ISRO) plans to launch its own satellite imaging system on its website within six months, according to the Indo-Asian News Service (IANS) on Thursday.
"We are going to launch our own satellite images on the web within six months from now. Our images are quite good and even better than Google," ISRO chairman G. Madhavan Nair disclosed here Thursday.
He said the law from being imaged has prohibited certain locations with security risks.
These locations will not be there, but the remaining places would definitely be on the net," he said.

Source :

Innovation: An Affordable GNSS Odometer

WHAT DO THE GREEK MATHEMATICIANArchimedes of Syracuse, the American statesman and polymath Benjamin Franklin, and the Mormon pioneer William Clayton all have in common? They each invented an odometer — a mechanical device for measuring distance. Whether we be military engineers, mail-route mappers, wagon masters, or just automobile drivers, we often want to know not just where we are but how far we have come.

The odometer was likely first invented by Archimides during the First Punic War when Syracuse got in the way of Rome during its battle with Carthage. A Greek origin is fitting as the word odometer derives from the Greek words hodós, meaning "path" or "way" andmétron, meaning "measure."

The device was reinvented many times over the years but its use was not widespread until the development of the automobile, and now virtually every vehicle sports one. Mechanical odometers gave way to electronic ones but the distance traveled was and is still determined by counting wheel revolutions. But just how accurate are the odometers in our modern vehicles? Not very, it seems. The odometer reading is affected by tire pressure, tire slip, and incorrect calibration. And while in many countries there is no regulation covering odometer accuracy, the Society of Automotive Engineers' voluntary standard and that of the European Commission is only plus or minus 4 percent, or as much as a 4-kilometer error in every 100 kilometers.

Does this matter? Well, in effort to reduce the cost to the general tax payer of maintaining roads or reducing conjestion, many administrations have implemented "road pricing," where a flat charge is levied for using a particular stretch of road or for entering a city center. But some administrations are charging per kilometer of travel with data coming from an odometer recording. Automobile insurance companies have also implemented plans where the premium is based on the distance traveled by the vehicle ("pay as you drive"). To fairly implement such schemes, governments should require more accurate odometers in vehicles. Could an odometer based on GNSS be a solution?
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Sunday, May 25, 2008

Loss of animal species and crops is “devastating”: UN chief

 UNITED NATIONS, May 25 (APP): The extinction of animal species, as well as the reliance on a narrow range of crops, is a major threat to the planet’s development and security, Secretary-General Ban Ki-moon has said. “This Day serves as a reminder of the importance of the Earth’s biodiversity, and as a wake-up call about the devastating loss we are experiencing as irreplaceable species become extinct at an unprecedented rate,” Ban said in a statement marking the International Day for Biological Diversity.

About a fifth of domestic animal breeds are at risk of extinction, with an average of one lost each month, and out of the 7,000 species of plants that have been domesticated over the 10,000-year history of agriculture, only 30 account for the vast majority of food consumed every day, according to U.N. environmental agency.

“Relying on so few species for sustenance is a losing strategy,” the Secretary-General said. “Climate change is complicating the picture,” he added, saying that livestock production accounted for more greenhouse gas emissions than transport.

“In a world where the population is projected to jump 50 per cent by the year 2050, these trends can spell widespread hunger and malnutrition, creating conditions where poverty, disease and even conflict can metastasize.”

In a separate statement marking the day, from the UN Environment Programme (UNEP) and the Convention on Biological Diversity, the CBD’s Executive Secretary Ahmed Djoghlaf said: “If current extinction rates continue, it will be hard to provide sufficient food for a global population that is expected to reach nine billion by mid-century.”

At the ongoing meeting on the CBD in Bonn, Germany, delegates are deciding on measures that would move the world closer to the globally-agreed goal of reversing the loss of biodiversity by 2010. Under the Convention, countries are working to protect soil biodiversity, curb the loss of pollinators, and maintain the variety of foodstuffs needed to ensure proper food and nutrition.


‘Effects of global warming worse than thought’

 Global warming is damaging the earth more quickly than previously forecast and rising oil prices threaten to speed the growth in greenhouse gas emissions, scientists and activists told environment ministers from industrialised nations on Saturday.

The ministers, from the Group of Eight countries, gathered in the western Japanese city of Kobe for a three-day conference dominated from the opening minutes by the battle with the worsening effects of climate change.

At a round-table discussion on Saturday afternoon, environmentalists urged quick action to stem the effects of the rise in world temperatures, which scientists say threaten to drive species to extinction, worsen floods and droughts, and thwart economic development.

The rapid melting of the Arctic ice, increasing crop damage and other problems show the multiplying effects of higher temperatures, said Bill Hare of the Potsdam Institute for Climate Impact Research.

Summer sea ice in the Arctic, for instance, shrank to a record low last year --- nearly 40 per cent less than the long-term average between 1979 and 2000.

Hare also warned that rising oil prices could speed that even further. Light, sweet crude for July delivery rose by $1.38 to settle at $132.19 a barrel on the New York Mercantile Exchange on Friday. The expense encourages the use of cheaper coal --- a much dirtier fuel.

“The recent developments in the energy sector, particularly high oil prices and coal-intensive development ... are pointing towards the risk of higher emissions,” Hare told ministers from G8 and observing nations.

“(It’s) too early to say if this is an entrenched change in the pattern ... but (it’s) certainly a risk factor,” he said.

The sessions take place in the midst of UN-led talks to conclude an international pact by December 2009 to combat global warming. The pact is aimed at succeeding the Kyoto Protocol, a climate change agreement whose first phase expires at the end of 2012.

The UN process, however, has moved slowly, with nations clashing over how ambitious the world should be in stemming the rising temperatures, how reduction targets should be set, and how much rapidly developing nations such as China should be called on to rein in emissions of greenhouse gases.

Yvo de Boer, the UN climate chief, told the Associated Press on the sidelines of the meeting that the environment ministers should set the stage for decisive movement on climate change at the G8 summit in Japan in July.—AP

Carbon Dioxide Pollution is Killing the Oceans

Whether or not carbon dioxide emissions cause global warming, they're very much a pollutant -- something that's been overshadowed by the climate change battle.

In an article published in Geophysical Research Letters, climate expert Ken Caldeira and colleagues argue that CO2 emissions will soon oversaturate the oceans; within four decades, they write, oceans could become dangerously acidic, literally corroding the plankton foundations of oceanic food chains.

Along the way, ocean water will no longer meet clean water standards established by the Environmental Protection Agency. Unfortunately, these aren't binding, and the EPA has resisted categorizing CO2 as a pollutant: warming, they've argued, isn't necessarily pollution.

If, however, other scientists back Caldeira's postulations, it'll be hard for the EPA to maintain its position. Granted, catastrophic predictions are not rare to science, and very few have come true; but this is really scary stuff. It'll be a lot easier to adapt to a warming planet than to dead oceans (unless, of course, we get both. Shudder.)

Saturday, May 24, 2008

The Carbon Sense Coalition » The Lynching of Carbon Dioxide - The Innocent Source of Life, by Dr. Martin Hertzberg

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Global Warming Denialists

“Global warming is not a global crisis” declared the Heartland Institute, organiser of the “International Conference on Climate Change”. Heartland is a well-known right-wing lobby group which accepted more than half a million dollars from oil giant ExxonMobil between 1999 and 2005, according to Exxon documents disclosed by Greenpeace, and thousands of dollars more from the tobacco industry.

Not surprisingly, in a statement issued Tuesday, they insisted that all efforts “intended to reduce emissions of CO2 be abandoned forthwith”.

“Manmade global warming is a total hoax. It has no basis in fact,” shouted Rush Limbaugh, a U.S. conservative radio host, on his Feb. 27 show, which draws as many as 13 million listeners.

“Record snows and cold are being reported from all over the northern hemisphere this winter,” Limbaugh claimed.

There is more to the northern hemisphere than the U.S. and Canada. Yes, it has also been cold in China and the Middle East, but it has also been very warm in Britain and most of Europe. In early February, it was balmy 14 degrees C in Edinburgh, Scotland, which is the city’s normal average temperature in July. In Moscow, Russia, the most northern capital city in the world, the forecast this week is rainy and about 3 degrees C, instead of the normal snowy and -10 degrees C.

These temperatures prove nothing. It is just weather. However, climate is completely different than the daily variations in temperature in any one place. Climate is the total of all weather occurring over a period of years in a given place. A cold January means it is winter in the U.S., nothing more.

But Limbaugh went on to claim that NASA’s Goddard Institute for Space Studies latest data shows that “global temperatures have dropped precipitously” in the last year, when in fact NASA reported that 2007 was the second warmest year on record.
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The Need for GIS in Urban Sustainability

The human population on planet Earth is about to reach a tipping point unique in its history. Sometime over the course of 2007 and 2008, the global human population will, for the first time, consist of more urban dwellers than rural dwellers (Lee 2007; UN-HABITAT 2006). Soon, if it has not already happened, the majority of the human species will live in sprawling cities where existing urban problems such as air and water pollution, traffic congestion and transportation, sprawl, sanitation, energy, public health, and local economic issues will be exacerbated. This changing dynamic between people and where and how they live on the Earth will have important repercussions for humanity’s future, especially in light of the growing evidence in support of global climate change and the growing need to find more sustainable ways of existing in this world.
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Designs on Moon

Later this year NASA plans to launch its first new missions to the moon in more than 35 years. The goal: To scope out likely spots to land and create a habitat where astronauts can stay for longer than the Apollo program ever dreamed.
But therein lies the controversy: Mars, with its potential stores of oxygen and water, has the highest potential for long-term human habitation. The moon, even in NASA’s manned spaceflight plans, isn’t supposed to be the primary destination for humans’ return to space. Some scientists are asking why we are working so hard to return to a place where we’ve already set foot.
NASA’s plans suggest that the lunar habitat is, to some extent, meant to be a kind of stepping stone, a field laboratory where scientists can test out new technologies, investigate how to mine the surface and figure out how to keep humans alive in the harsh lunar environment. It’s a classroom and staging ground before taking the much bigger and more dangerous leap to Mars.
Meanwhile, the moon is no longer the finish line in a race between two superpowers; instead, other nations are joining in. In addition to the U.S. and Russia, China, Japan, India and other nations have announced plans or have already launched missions of their own to assess and stake a claim in the new era of the space race.
When we last set foot on the moon in 1972, no one imagined it would be more than three decades before we would return. Plans to return humans to the moon are under way - but will the moon be a stepping stone to Mars or a destination all its own?
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In the twilight sky, low on the horizon, glows a brilliant body. Occasionally mistaken for a UFO, the planet is actually our nearest neighbor and Earth’s twin: Venus. Earth and Venus share a similar mass, volume and distance from the sun. Scientists even think the two planets were birthed from the same parent material some 4.5 billion years ago. But while Earth was developing into a thriving planet filled with life, Venus went down a wayward path, becoming Earth’s “evil” twin: a hellishly hot world enveloped by a thick, toxic atmosphere. “It’s like having two chocolate cake mixes and one comes out a lemon cake,” says Ellen Stofan, a Venus researcher at Proxemy Research, Inc. in Laytonsville, Md.
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GIS Officer Needed in Australia

Job Location(s):
New South Wales - Cessnock
This role is only available to residents of Australia
or to those who hold valid working visas or permits

Reference: 2008/30



To provide specialist technical advice in the development and maintenance of the geographic information system and work with and train system users to ensure effective and efficient use of the geographic information system.

1. Ensure the effective operation and integrity of the geographic information system (Mapinfo). • Specialist advice on MapInfo is provided to end users to improve service levels and corporate knowledge and understanding of the land information system.
• The integrity of property information is constantly monitored and maintained between the geographic information system(Mapinfo) and the mainframe system (Authority).
• Requests are attended to within agreed service levels, whilst keeping the end user fully informed of progress.
• The integrity of the data for input into the Mapinfo system is maintained at all times to ensure accuracy.
• Users are educated to the appropriate levels in the Mapinfo system to ensure integrity of system and data is maintained.

2. Co-ordinate the capture and maintenance of graphical and attribute data. • Ensures accuracy of data captured and entered by system users.
• Identifies areas for improvement in the system and liaises with users to increase outcomes from the land information system.
• Identifies training needs of users and develops training programmes as required.
3. Develop the land information systems to meet present and future organisational requirements. • Land information applications are investigated and developments/ improvements to the system identified and reported to Information Technology Co-ordinator.
• Agreed improvements to the land information systems are implemented in accordance with Council policy and procedure and within agreed time frames.
• Effective communication with end users of the geographic information system is maintained at all times to encourage feedback on the operation of the system and ensure customer/client focus is maintained and improved.
4. Provide assistance in the operation and use of the geographic information system and other relevant software applications. • Troubleshooting on specific applications is undertaken as required and within agreed service levels.
• End users are informed of progress of requests.
• Requests are monitored to determine if training is required for end users to improve use of appropriate software.
• Effective communication and feedback is maintained with customers/clients at all times.

5. Develop or assist departments to develop corporate and departmental applications as required. • Client needs are clarified and appropriate application solution discussed.
• Applications are developed in consultation with end users and Information Technology Co-ordinator.
• Applications are installed with nominated end users within agreed time frames.
• Training needs of end users are identified and training programme is developed.
• End users are trained in the use of the application.
• Specialist advice on appropriate course of action is provided and may include referral to external providers.
• Systems are investigated to identify opportunities for development of new applications.
• Information is sought from end users, managers and Directors to identify current and future needs.
6. Work co-operatively with and provide backup to the Network Support Officer and other Information Technology staff to support users and develop applications. • Co-operative approach is maintained at all times.
• Specialist advice and assistance is provided as required.
• Consultation and feedback is maintained with all appropriate officers and end users at all times.
• Applications are developed in accordance with procedures and within required time frames.
7. Develop applications and/or extract data from Authority system as required. • Requirements of application are identified.
• Application is developed in consultation with end users and Information Technology Co-ordinator.
• Applications are installed with nominated end users within agreed time frames (if required).
• Training needs of end users are identified and training programme developed (if required).
• End users are trained in use of application (if required.

1. Ensures client needs are served in a timely and efficient manner in respect of the range of services provided.

2. Undertakes relief of other Information Technology positions (as required and within the scope of skill and competency) when required for periods of planned leave.

3. Carries out such other tasks and responsibilities as may be required and assigned from time to time.

4. Promotes the public and corporate image of both the Council and Department in all business relations.

5. Promotes a climate of trust, Council loyalty and teamwork throughout the Section and Department.

6. Assists in the implementation of Council’s policies and decisions.

7. Complies with Council’s Code of Conduct, ensuring probity and ethical behaviour in all dealings.

8. Monitors work practices and procedures continually, with a view to improving service delivery, and ensuring they meet statutory and corporate Occupational Health & Safety requirements.

9. Supports client/supplier relationships across the Council to promote understanding within areas of responsibility.


Essential Requirements

• Possess formal qualifications in Information Technology (or related field) to at least TAFE Certificate IV level.
• Sound knowledge in computerised geographic information systems (Mapinfo or equivalent)
• Demonstrated experience in GIS and writing applications.
• Demonstrated strong computer skills in Windows based applications.
• Demonstrated customer service skills.
• Demonstrated effective communication and interpersonal skills.
• Current Class C drivers license.
• Proven commitment to working within a team environment.

Desirable Requirements

• Experience in local government.
• Experience in LIC/DCDB data.
• Experience with networks.
• Experience in developing database applications in Microsoft Access and linking them to Mapinfo.
• Ability to work effectively with users in a proactive manner.
• Experience with Mapinfo third party software, Cadastral Mapper, DigiTools, EasiMaps.
• Experience in the use of a Digitiser.
• Tertiary qualifications in computer science, mapping, surveying or geography.
• Workplace Assessor certificate
• Network PC support
Additional Information
Salary: from $990.00 AUD up to $1,109.00 AUD per week
Position Type: Full Time, Employee
Required Education Level: Technical/Vocational
Relocation funds available
Job Starting Date: June 30, 2008
Job Closing Date: May 30, 2008
Study Assistance
Cessnock City Council

P O Box 152
Cessnock, 2325
New South Wales, Australia
Phone Number: (02)4993 4189
Fax Number: (02)4993 2500
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