Monday, June 30, 2008

Gondi People

The Gonds are one of the most famous and important tribes in India, known for their unique customs and traditions. They are mainly a nomadic tribe and call themselves as Koytoria. The term ‘Gond’ is derived from the Telugu word ‘Konda’ which means hill. Gond Tribes are primarily located in Madhya Pradesh, Chhattisgarh, eastern Maharashtra, northern Andhra Pradesh and western Orissa. With a population of over 4 millions, Gonds also form the largest tribal group in central India. In Chhattisgarh, Gonds are the largest tribal group in terms of population and are mainly concentrated in the southern part of the state. More than 20 % of Gonds in Chhattisgarh live in Bastar region only. There are 3 major sub-castes of Gonds in Bastar - Maria, Muria and Dorla.

The Gonds are predominantly Hindus and like to live to live in groups in small villages. The main language of the Gonds is Gondi but about half of Gond populations also speak Indo-Aryan dialects including Hindi. The Gonds are traditionally agriculturalists and some practice shifting cultivation even today. Other major activities of Gonds include collecting forest produce, fishing, hunting, forging metal goods in cottage industries and other primary sector activities. Gonds also have a special skill that has been passed down every generation and that is the secrets of the medicine plants. As there are no proper health facilities in several areas, they still follow the traditional system of medicines and use plants and herbs for curing various ailments. Gonds are also known for practicing social hierarchy system like Hindus and the Gond society is regarded as highly stratified and not conforming to the usual image of egalitarianism among tribals.

Sunday, June 29, 2008

Satellite pictures tell of human rights violation

USA – The term 'the morality of altitude' was coined to apply to bomber pilots who released their payloads on victims they couldn't see, without ever feeling any sense of remorse or empathy for the people whose lives, families, homes and property they destroyed.

A new initiative by the American Association for the Advancement of Science, publisher of the journal Science could well give the term a completely opposite and far more positive meaning. 

A project launched by the AAAS aims to use satellite imagery to provide evidence of human rights atrocities that have been denied by the governments that perpetrate them. 

The AAAS worked with Human Rights Watch to produce a 130-page report on attacks on eight villages across the remote Ogaden region of eastern Ethiopia, where "before" and "after" satellite images of villages identified by Human Rights Watch were analysed by Lars Bromley of the AAAS. 

It's confronting read, but the really damning evidence lies in the 'before' and 'after' images, which show blackened fields and destroyed homes where before there were whole villages. 
HRW's Peter Bouckaert said that the project was in response to frequent denials by the Ethiopian government that the massacres were happening at all. 

"The Ethiopian authorities frequently dismiss human rights reports, saying that the witnesses we interviewed are liars and rebel supporters," Mr Bouckaert said. "But it will be much more difficult for them to dismiss the evidence presented in the satellite images, as images like that don't lie." 

Source :

North Pole could be ice-free this summer, scientists say

The North Pole may be briefly ice-free by September as global warming melts away Arctic sea ice, according to scientists from the National Snow and Ice Data Center in Boulder, Colorado.
Full story

Thursday, June 26, 2008



                                                  Gypsum rocks are sedimentary rocks made up of sulfate mineral and formed as the result of evaporating sea water in massive prehistoric basins. It is very soft and is used to make Plaster of Paris, casts, molds, and wallboards
Gypsum rock is usually white or gray, and a freshly broken piece sparkles in the light. Selenite, which is pure gypsum, is the main mineral in gypsum rock; other minerals found in gypsum rock are calcite and anhydrite. It forms from the evaporation of salt-water lakes in semi-desert or desert areas. Gypsum rock is common throughout the United States. It is used to make Plaster of Paris and filler materials.

Gypsum is a soft mineral, hydrous calcium sulfate. Gypsum is the standard for hardness degree 2 on the Mohs mineral hardness scale. Your fingernail will scratch this mineral—that's the simplest way to identify gypsum. The clear variety that makes up this wedge is called selenite after the pearly luster of its cleavage faces, likened to moonlight. 
Gypsum also forms concretions of selenite blades called desert roses or sand roses, growing in sediments that are subjected to concentrated brines. The crystals grow from a central point, and the roses emerge when the matrix weathers away. They don't last long at the surface, just a few years, unless someone collects them. Here's another one.
Gypsum also forms concretions of selenite blades called desert roses or sand roses, growing in sediments that are subjected to concentrated brines. The crystals grow from a central point, and the roses emerge when the matrix weathers away. They don't last long at the surface, just a few years, unless someone collects them. Here's another one.
read more

Friday, June 20, 2008


     ●ANALYSIS - What & Why? :
  The heart of GIS is the analytical capabilities of the system. What distinguish the GIS system from other information system are
  its spatial analysis functions. Although the data input is, in general, the most time consuming part, it is for data analysis that 
  GIS is used. The analysis functions use the spatial and non-spatial attributes in the database to answer questions about the real 
  world. Geographic analysis facilitates the study of real-world processes by developing and applying models. Such models
  illuminate the underlying trends in geographic data and thus make new information available. Results of geographic analysis can
  be communicated with the help of maps, or both. 

  The organization of database into map layers is not simply for reasons of organizational clarity, rather it is to provide rapid access
  to data elements required for geographic analysis. The objective of geographic analysis is to transform data into useful information
  to satisfy the requirements or objectives of decision-makers at all levels in terms of detail. An important use of the analysis is the 
  possibility of predicting events in another location or at another point in time. 

  ●ANALYSIS -How? 
  Before commencing geographic analysis, one needs to assess the problem and establish an objective. The analysis requires 
  step-by-step procedures to arrive at the conclusions. The range of geographical analysis procedures can be subdivided into the
  following categories.  

  o Database Query. o Overlay. o Proximity analysis.  

  o Network analysis. o Digital Terrain Model. o Statistical and Tabular Analysis. 

   ● Use of Spatial Analysis: It helps us to: 

  o Identify trends on the data.

  o Create new relationships from the data. 

  o View complex relationships between data sets. 

  o Make better decisions. 

  ●Geographic Analysis: 
  It is the analysis of problems with some Geographic Aspects. 

  o Alternatives are geographic locations or areas. 

  o Decisions would affect locations or areas. 

  o Geographic relationships are important in decision-making or modeling. 
read on


  Successful implementation of GIS requires planning the project before its actual implementation. Planning leads to a 
  better structured and organized system.


  Phase 1-Planning
  A planning process is the first stage in the life cycle. This phase involves a systematic review of users, their data, and their 
  information needs. Decision makers are told about the costs and benefits of GIS and to include potential users in the 
  planning process so that they receive an overview of the technology. 
  Phase 2-System Design 
  The design phase matches user needs to GIS functionality. Design includes not only selection of hardware and software, but
  also the design of the GIS spatial and attribute database. A Relational database is generally used for the GIS. The 
  Database design will include specifications for scale, projection, and coordinate systems. Data is be tracked using a
  "Data Dictionary." During the design phase an incremental plan is often used for implementation of the technology. Incremental
  implementation means that users will build a GIS piece-by-piece. In some cases a ‘Prototype’ is developed so that refinements 
  can be made before finalizing the fully implemented system. 
  Phase 3-Implementation 
  During the implementation phase, attention to all user needs must be provided through training and education. Hands-on users 
  must be trained to utilize and maintain the system and the database. All types of users should be made cognizant of how the
  GIS will affect them and their data processing tasks. They must also be made aware of the changes that GIS will introduce 
  in the area of information generation and decision making.

  Phase 4-Maintenance 
  Finally, a GIS application must be maintained and kept current in terms of data and user support. In some cases, a GIS is 
  designed to meet the needs of a specific, finite project. In other instances, GIS is used to support an on-going mission or 
  program. In the former case, the GIS application will terminate once the project is completed and maintenance will probably 
  not be an issue. However, even if the initial GIS application is no longer being utilized, the data generated for the initial 
  project may be useful to other projects or users. In those instances, a current data dictionary will be vital for determining the 
  utility of the existing digital data for other uses. 

  In the case of an on-going GIS effort the system must be kept up-to-date in order to fulfill its design goals. Maintenance includes
  updating hardware and software, adding new data and updating existing data records, and keeping users current in terms of 
  system functionality



More About Cracks in India

click here

Thursday, June 19, 2008


Dear Readers
It is regarding the earlier post Msterious cracks........
One Earth_Science_India group member Dr. Raed Ahmad has suggested tht these cracks are sinkholes. I am Publishing what he posted.
Sinkholes are common where the rock below the land surface is limestone, carbonate rock, salt beds, or rocks that can naturally be dissolved by ground water circulating through them. As the rock dissolves, spaces and caverns develop underground. Sinkholes are dramatic because the land usually stays intact for a while until the underground spaces just get too big. If there is not enough support for the land above the spaces then a sudden collapse of the land surface can occur. These collapses can be small, as this picture shows, or they can be huge and can occur where a house or road is on top.
What is a "Sinkhole"?
A sinkhole is an area of ground that has no natural external surface drainage--when it rains, all of the water stays inside the sinkhole and typically drains into the subsurface. Sinkholes can vary from a few feet to hundreds of acres and from less than 1 to more than 100 feet deep. Some are shaped like shallow bowls or saucers whereas others have vertical walls; some hold water and form natural ponds. Typically, sinkholes form so slowly that little change is seen in one's life- time, but they can form suddenly when a collapse occurs. Such a collapse can have a dramatic effect if it occurs in an urban setting.
Areas prone to collapse sinkholes
The map below shows areas of the United States where certain rock types that are susceptible to dissolution in water occur. In these areas the formation of underground cavities can form and catastrophic sinkholes can happen. These rock types are evaporites (salt, gypsum, and anhydrite) and carbonates (limestone and dolomite). Evaporite rocks underlie about 35 to 40 percent of the United States, though in many areas they are buried at great depths.

Types of sinkholes
Since Florida is prone to sinkholes, it is a good place to use to discuss some different types of sinkholes and the geologic and hydrologic processes that form them. The processes of dissolution, where surface rock that are soluble to weak acids, are dissolved, and suffosion, where cavities form below the land surface, are responsible for virtually all sinkholes in Florida. 
Dissolution sinkholes
 Dissolution of the limestone or dolomite is most intensive where the water first contacts the rock surface. Aggressive dissolution also occurs where flow is focussed in preexisting openings in the rock, such as along joints, fractures, and bedding planes, and in the zone of water-table fluctuation where ground water is in contact with the atmosphere.
Cover-subsidence sinkholes
Cover-subsidence sinkholes tend to develop gradually where the covering sediments are permeable and contain sand. In areas where cover material is thicker or sediments contain more clay, cover-subsidence sinkholes are relatively uncommon, are smaller, and may go undetected for long periods.
Cover-collapse sinkholes
Cover-collapse sinkholes may develop abruptly (over a period of hours) and cause catastrophic damages. They occur where the covering sediments contain a significant amount of clay. Over time, surface drainage, erosion, and deposition of sinkhole into a shallower bowl-shaped depression.
Sinkholes can be human-induced
New sinkholes have been correlated to land-use practices, especially from ground-water pumping and from construction and development practices. Sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Some sinkholes form when the land surface is changed, such as when industrial and runoff-storage ponds are created. The substantial weight of the new material can trigger an underground collapse of supporting material, thus causing a sinkhole.
The overburden sediments that cover buried cavities in the aquifer systems are delicately balanced by ground-water fluid pressure. The water below ground is actually helping to keep the surface soil in place. Ground-water pumping for urban water supply and for irrigation can produce new sinkholes In sinkhole-prone areas. If pumping results in a lowering of ground-water levels, then underground structural failure, and thus, sinkholes, can occur.

GPS on a growth path

Global Positioning System (GPS) provides unequaled accuracy and flexibility of positioning for navigation, surveying and geographic information system (GIS) data capture. Its growing use in automotive and consumer applications is propelling the market for mobile location technologies. Although standalone products are quite popular, the most common applications are built around Portable Navigation Devices (PNDs), mobile phones, or car navigation systems. Moreover, the technology is fast gaining acceptance worldwide, as it is penetrating into previously untapped areas. 

GPS companies, both local and international, are competing to grab a piece of this market, especially in logistics for tracking cargo and trucks across India. Lately, the GPS market has started picking up in the country and competition between GPS device providers such as Garmin and inbuilt GPS provider in phone like Nokia has begun. Along with this, we already have maps and static navigation systems available for free or at cheap rates. 

Globally, the GPS market is expected to exceed $30 billion in this financial year, as the market is being flooded by a number of affordable GPS components and receivers. As far as the Indian market is concerned, a relatively large number of players have entered the navigation market, which in turn depicts that the potential for development in the market is significant and that the industry will surge in years to come.


Any organization, government private is in some way or another strongly linked to the geography in which it operates. A GIS that
has been designed in a proper manner has the capability of providing quick and easy access to large volumes of data of these
geographical features. The user can access & select information by area or by theme to merge one data set with another, to
analyze spatial characteristics of data, to search for particular features, to update quickly and cheaply and asses alternatives.

In simpler terms, GIS allows the user to understand geographic information in an easy manner without having to go
through large volumes of confusing data that is in tabular form. Visualizing the geography of a particular location is
no doubt easier that trying to analyze raw data.

The potential and substantial benefits of using GIS makes it a very important tool making the work of any
organization easier and more productive. Some of the potential benefits of GIS are:
♦ Opportunity to reduce sets of manual maps held and associated storage costs.
♦ Faster and more extensive access to geographic information.
♦ Improved analysis e.g.of areas, distances, patterns, etc.
♦ Better communication of information to public officers, members.
♦ Improved quality of services.
♦ Better targeting and coordination of services.
♦ Improved productivity in providing public information.
♦ Improved efficiency in updating maps.
♦ The ability to track and monitor growth and development over time.
♦Improved ability to aggregate data for specific sub areas.

Thus GIS’s have become indispensable tools for governance, commerce, and environmental and social scien

Mysterious Cracks in India

On Earth_Science_India group on Yahoo Rameshji posted photographs of cracks in banda, Hamirpur, and Allahabad in India. These cracks are widespread, they are wide and also up to extent of 100 m or so.

It will be intersting to find out orientation of such cracks! Sudden emergence of such widespread cracks, need attention of Geoscientists!
click here to see photographs

PhD student Position

The Institute of Geophysics, University of Göttingen has an exciting 
opening for a highly 
motivated, high calibre student wishing to pursue studies leading to 
a PhD, starting 1st 
October 2008. The successful candidate, who will have a strong 
background in physics, will 
analyse model and interpret high-quality electromagnetic depth 
sounding (magnetotelluric and 
GDS) data from Queensland, with reference to geodynamic models of 
plate motion and 
mantle flow. Employment will be according to German TV-L 13/2 for up 
to three years. The 
thesis may be written in English or German. The closing date for 
applications is 1st July 2008. 
Enquiries and applications should be addressed to the project 

Dr. Fiona Simpson 
Institut für Geophysik

Fakultät für Physik 
Friedrich – Hund – Platz 1 
37077 Göttingen, Germany 

The Georg-August-University is an equal opportunities employer and is 
committed to raising 
the proportion of women scientists. As such, applications from 
suitably-qualified women are 
strongly encouraged. Applications from candidates with severe 
disabilities are also 
particularly encouraged.

Wednesday, June 18, 2008

Cartosat 2A can help Kerala's Waterway project - Dr. Kalam

Former President A.P.J.Abdul Kalam the other day urged the Indian Space Research Organisation (ISRO) to use its remote sensing facilities and inputs from the Cartosat-2 mapping satellite to help the Kerala government develop the Manjeswaram-Kovalam Waterway.

Kalam was addressing a function organised by ISRO and Asianet on May 31 to honour ISRO scientists instrumental for the successful PSLV-C9 launch last month.

"Chief Minister V.S.Achuthanandan spoke passionately about the waterway project when we met. I request the ISRO to use its remote sensing and Cartosat- 2 capabilities for the project," Kalam said.

Creation of waterways across the country and interlinking of rivers, he said, are among the important infrastructural necessities in developing food, economic and national security.

The ISRO, with its current and planned space infrastructure, can play a great role in bridging the rural urban divide and providing education and healthcare for all.

It has to gear itself up for providing valuable space inputs to tackle water scarcity, promote energy independence and increase agricultural productivity, he said.

The Youth Satellite the ISRO proposes to launch by the beginning of 2009 will be a platform connecting the youth of multiple countries, Kalam said.

The satellite, he said, will definitely be a `trigger for new thinking and innovation.’ Co-ordinated development of agriculture and food processing, education and healthcare, information and communication technology and infrastructure will lead to food, economic and national security, he said.

The ISRO should increase the research base in the country which is crucial for the future aspirations of the space agency, he said. World Space Vision 2050 (suggested by Kalam to the world space community) will enhance the quality of life, inspire the spirit of space exploration, expand the horizons of knowledge and ensure space security for all nations, he said. It was also essential to create a World Space Council to oversee planning, and implementation of large-scale and societal missions like energy from space, space security and deep space exploration, he said.

Source :

Tuesday, June 17, 2008

Africa: Famine Early Warning System Can Predict Food Shortages

              USA - USAID established the famine early warning system (FEWS) to help prevent or respond to famine conditions in sub-Saharan Africa by giving decision makers specific information about drought conditions or dwindling crop yields based on satellite remote-sensing data.

Satellite sensors acquire images of the Earth and transmit the data to ground receiving stations worldwide. Once the raw images are processed, analysts can document changing environmental conditions like pollution, global climate change, natural resource distribution and urban growth.

In this effort, USAID partners with NASA, the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS) and the U.S. Department of Agriculture in the United States, and collaborates with international, regional and national partners. Chemonix International, a global development firm, implements the program for USAID.

In 2000, the FEWS Network (FEWS NET) was formed to establish more effective, sustainable, African-led food security and partnerships to reduce the vulnerability of at-risk groups to famine and floods.

"At the beginning, it was primarily remote sensing," Gary Eilerts, USAID program manager for FEWS NET, told "It was pretty much looking at rainfall and vegetation and trying to say what we thought was happening in terms of food security."

Source :

Monday, June 16, 2008

Map Analysis in GIS

ANALYSIS - What & Why? :
The heart of GIS is the analytical capabilities of the system. What distinguish the GIS system from other information system are
its spatial analysis functions. Although the data input is, in general, the most time consuming part, it is for data analysis that
GIS is used. The analysis functions use the spatial and non-spatial attributes in the database to answer questions about the real
world. Geographic analysis facilitates the study of real-world processes by developing and applying models. Such models
illuminate the underlying trends in geographic data and thus make new information available. Results of geographic analysis can
be communicated with the help of maps, or both.

The organization of database into map layers is not simply for reasons of organizational clarity, rather it is to provide rapid access
to data elements required for geographic analysis. The objective of geographic analysis is to transform data into useful information
to satisfy the requirements or objectives of decision-makers at all levels in terms of detail. An important use of the analysis is the
possibility of predicting events in another location or at another point in time.

Before commencing geographic analysis, one needs to assess the problem and establish an objective. The analysis requires
step-by-step procedures to arrive at the conclusions. The range of geographical analysis procedures can be subdivided into the
following categories.

o Database Query. o Overlay. o Proximity analysis.

o Network analysis. o Digital Terrain Model. o Statistical and Tabular Analysis.

● Use of Spatial Analysis: It helps us to:

o Identify trends on the data.

o Create new relationships from the data.

o View complex relationships between data sets.

o Make better decisions.

●Geographic Analysis:
It is the analysis of problems with some Geographic Aspects.

o Alternatives are geographic locations or areas.

o Decisions would affect locations or areas.

o Geographic relationships are important in decision-making or modeling.

Some examples of its applications:
o Nearest Neighbour.
o Network distances.
o Planar distances.


What is GIS?

GIS allows us to view, understand, question, interpret, and visualize data in many ways that reveal relationships, patterns, and trends in the form of maps, globes, reports, and charts.

A GIS helps you answer questions and solve problems by looking at your data in a way that is quickly understood and easily shared.

GIS technology can be integrated into any enterprise information system framework.

Three Views of a GIS

A GIS is most often associated with a map. A map, however, is only one way you can work with geographic data in a GIS, and only one type of product generated by a GIS. A GIS can provide a great deal more problem-solving capabilities than using a simple mapping program or adding data to an online mapping tool (creating a "mash-up").

A GIS can be viewed in three ways:
The Database View: A GIS is a unique kind of database of the world—a geographic database (geodatabase). It is an "Information System for Geography." Fundamentally, a GIS is based on a structured database that describes the world in geographic terms.

The Map View: A GIS is a set of intelligent maps and other views that show features and feature relationships on the earth's surface. Maps of the underlying geographic information can be constructed and used as "windows into the database" to support queries, analysis, and editing of the information. Learn more.

The Model View: A GIS is a set of information transformation tools that derive new geographic datasets from existing datasets. These geoprocessing functions take information from existing datasets, apply analytic functions, and write results into new derived datasets. Learn more.

By combining data and applying some analytic rules, you can create a model that helps answer the question you have posed. In the example below, GPS and GIS were used to accurately model the expected location and distribution of debris for the Space Shuttle Columbia, which broke up upon re-entry over eastern Texas on February 1, 2003. Learn more about this project.

Together, these three views are critical parts of an intelligent GIS and are used at varying levels in all GIS applications
read more

Sunday, June 15, 2008

Japanese Company Unveiled Water-fuel car

Japanese company Genepax presents its eco-friendly car that runs on nothing but water.

The car has an energy generator that extracts hydrogen from water that is poured into the car’s tank. The generator then releases electrons that produce electric power to run the car. Genepax, the company that invented the technology, aims to collaborate with Japanese manufacturers to mass produce it.
originally posted by:

Solar Power Starts to Sizzle

ALTERNATIVE ENERGY Global production of solar photovoltaic (PV) cells increased 51% in 2007, to 3,733 megawatts, according to a report from the Worldwatch Institute, Washington, D.C., and Prometheus Institute, Cambridge, Mass. More than 2,935 megawatts.
full story

New soil analysis aims to improve land use

Scientists have investigated different components of variation in soil at diverse scales ranging from the nanoscale to entire biomes in order to improve predictions of soil processes and subsequently land use.

Soil variation occurs across multiple geographic scales ranging from vast climatic regions of the Earth to a 50 acre farm field to the molecular world of soil nano-particles in a pinch of soil.
Though many approaches have been used to examine soil variation at these diverse scales, there is a common difficulty among methods in separating out random variations from systematic variations.

Saturday, June 14, 2008

Scope of Remote Sensing

Definition of Remote Sensing

Remote sensing can be defined as the technique of obtaining information about objects through the analysis of data collected by instruments that are not in physical contact with the objects of investigation.
Remote vs In Situ Sensing

Remote sensing differs from in situ sensing in which the measurement instrument is in contact with the object being measured. For example, it is possible to obtain information about soil temperature using either in situ or remote sensing. In situ sensing could be conducted by pushing a thermometer into the soil and recording the soil temperature at selected sample points. Interpolation techniques could be applied to the sample point data to create a continuous soil temperature surface within the study area of interest. This data collection process is expensive, difficult to replicate - especially in remote study areas, and is subject to both measurement and interpolation errors.

Similar temperature information can be collected by remote sensing using optical-mechanical scanners that are sensitive to the thermal infrared portion of the electromagnetic spectrum. Infrared imagery has often been used to assess the energy efficiency of buildings. An infrared image taken in winter when the outside temperature is cold will clearly show where heat is being lost. Windows, doors or areas with poor insulation appear as bright spots on a thermal infrared image because they are at a higher temperature than the exterior surface of well insulated walls. Airborne or satellite sensors that detect infrared radiation could be used to obtain a soil temperature map without having to rely on interpolation between sample points. This method can be cheaper than in situ sensing, and in the case of satellite imagery, can be repeated to obtain multi-temporal images.

There are many types of remote sensors. The human eye and ear are passive remote sensors. Passive remote sensors do not emit energy but simply detect energy that is reflected or propogated back to the sensing device. The eye detects energy in the visible portion of the electromagnetic spectrum while the ear detects sounds sound energy. The photographic camera, used in daylight without flash, is a passive remote sensor as are airborne or spaceborne multispectral scanners such as Landsat MSS, Thematic Mapper or SPOT that have been widely used in environmental remote sensing. Active remote sensors emit energy and then detect the emitted energy that gets reflected back off an object. The photographic camera used with a flash, radar and laser systems used by police to catch speeders, sonar used for bathymetric mapping, and spaceborne radar systems are examples of active remote sensors. In the context of environmental remote sensing, passive remote sensing systems have been the most widely used but active remote sensing systems such as radar offer significant advantages in that they can penetrate clouds and so do not require clear sky conditions.
Stages in the Remote Sensing Process

The remote sensing process involves two stages: data collection and data analysis. Data collection is accomplished through the use of remote sensing devices that record data on photographic film or as digital data. The resulting data provide a synoptic view of a portion of the Earth's surface. but require analysis and interpretation in order to provide meaningful information. This can involve either visual interpretation, which has been the predominant mode of airphoto interpretation, or digital analysis, which has been widely used in processing satellite imagery. Remote sensing remains both an art and a science because there is often no obvious, well-documented choice of data collection devices or analysis and interpretation techniques that are best suited to a particular applied problem situation.
Electromagnetic Radiation (EMR)

Energy is the capacity to do work. Energy can take many forms such as light, heat or sound, and can be transmitted between objects through three processes: conduction, convection and radiation. Conduction requires that the objects be in direct physical contact. Energy is transferred from the high energy object to the low energy object until both objects are at the same energy level. For example, a hot water bottle warms a bed until the hot water bottle and the bed reach the same temperature, after which no further energy transfer occurs. Convection occurs in liquids and gases. Convection is based on currents that distribute energy throughout the volume of liquid or gas. Radiation does not require physical contact or the existence of a liquid or gas.

Environmental remote sensing systems focus on electromagetic energy which is a dynamic form of energy caused by the oscillation or acceleration of an electrical charge. All objects that have a temperature higher than absolute zero (0o K or -273.16o C) emit electromagnetic energy. The wavelength of the emitted energy is a function of temperature.
read on

United Nations Warns Biofuels Could Fuel Deforestation, Land Disputes

The world's rush to embrace biofuels is causing a spike in the price of corn and other crops and could worsen water shortages and force poor communities off their land, a U.N. official said Wednesday.

Speaking at a regional forum on bioenergy, Regan Suzuki of the U.N.'s Food and Agriculture Organization acknowledged that biofuels are better for the environment than fossil fuels and boost energy security for many countries.

However, she said those benefits must be weighed against the pitfalls many of which are just now emerging as countries convert millions of acres to palm oil, sugar cane and other crops used to make biofuels.

"Biofuels have become a flash point through which a wide range of social and environmental issues are currently being played out in the media," Suzuki told delegates at the forum, sponsored by the U.N. and the Thai government.

Foremost among the concerns is increased competition for agricultural land, which Suzuki warned has already caused a rise in corn prices in the United States and Mexico and could lead to food shortages in developing countries.

She also said China and India could face worsening water shortages because biofuels require large amounts of water, while forests in Indonesia and Malaysia could face threats from the expansion of palm oil plantations.

"Particularly in the Asia-Pacific region, land availability is a critical issue," Suzuki said. "There are clear comparative advantages for tropical and subtropical countries in growing biofuel feed stocks but it is often these same countries in which resource and land rights of vulnerable groups and protected forests are weakest."

Initially, biofuels were held up as a panacea for countries struggling to cope with the rising cost of oil or those looking to reduce greenhouse gas emissions. The European Union, for example, plans to replace 10 percent of transport fuel with biofuels made from energy crops such as sugar cane and rapeseed oil by 2020.

But in recent months, scientists, private agencies and even the British government have said biofuels could do more harm than good. Rather than protecting the environment, they say energy crops destroy natural forests that actually store carbon and thus are a key tool in the fight to reduce global warming.

Some of those doubts were on display Wednesday at the U.N. forum, with experts saying many countries in Asia have rolled out plans to mandate biofuels for transport without weighing the potential risks.

Thailand, for example, is considering delaying the introduction of diesel blended with 2 percent biofuel for two months until April because of palm oil shortages, while the Philippines is considering shelving a biofuels law over concerns about the negative environmental effects.

India is facing criticism that its plans to plant 30 million acres of jatropha trees by 2012 for biofuel could force communities from their land and worsen deforestation. There are also concerns that it will be unable to find the 100 million acres of vacant land it needs to grow the shrub-like plants.

Varghese Paul, a forest and biodiversity expert with the Energy and Resources Institute in India, said dependence on a single species is dangerous.

"An outbreak of pests and diseases could wipe out entire plantations in one stroke," Paul said.

Friday, June 13, 2008


An unusually active sunspot region is now crossing the Sun. The region, numbered 875, is larger than the Earth and has produced several solar flares over the past week. It should take a few more days for Sunspot 875 to finish crossing the solar disk. The above image of the Sun was taken last Wednesday in a very specific color of red light to bring up detail. Sunspot 875, in the midst of erupting a large Class C solar flare, can be seen as the dark region to the upper right. In the above image, relatively cool regions appear dark while hot regions appear bright. On the far left, solar prominences are visible hovering above the Sun's surface.

Visit to Sun

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Dates announced for GPS and GIS training in Bhutan

Bhutan - The GPS and GIS has now become a multifunctional and versatile tool for resource
management and also for any other purposes.

                     The GPS and GIS have become important for the community forestry programme at this juncture. Without having good and realistic maps, the community forest management plan will be incomplete. Map for the CFM plan is very crucial for understanding of CF sites, recording the CF sites in digital form and monitoring the CF in future.

The training on GPS and GIS will be conducted by the College of Natural Resources in close collaboration with the Social Forestry Division, Department of Forests from 23rd to 27th June 2008 at College of Natural Resources Computer Lab. The training is financially supported by the Participatory Forest Management Project (PFMP).

The objectives of the Training:
To equip dzongkhag forestry staff with essential knowledge and skills on GPS and GIS;

To be able to maintain database of CF applying GIS techniques;

To be able to backstop the field staff in surveying and mapping of CF boundary;

To be able to monitor and report on the status of CF management activities from the respective dzongkhags to Headquarters on an annual basis; and

To be able to make maps and keep data in digital form.

Target group for the training is the dzongkhag forestry and social forestry staff.

Source :

Nepal : District land revenue office, Syangja, has started putting land ownership certificates in computers with a view to providing fast and efficient services to the public.

The move is aimed at modernizing the office’s services, reducing the gap between the office and the customers and promoting services based on ICT.

The project assisted by economic counseling unit of the monitoring division of the National Planning Commission, said chief of the office Raju Poudel. He said the information is stored into GIS-based software and Syangja was one among the five districts including Kathmandu and Kaski selected for computerisation of the land revenue offices.

The task of putting the information on landownership has been given to Pokhara-based Skillnet Pvt Ltd. There are 125,000 landowner certificates for around 800,000 plots in Syangja.
The work has begun since a month ago and it will complete within six months, the office said. So far information on 200,000 plots of land has been put into computers. The office has arranged seven computers for the project.

Account chief of the office Ananta Marasini said the computerization of the land information will make the services efficient and it will also ensure the safety of landownership certificates. It will also make the office’s work transparent.

Around 100,000 land ownership certificates were burnt to ashes in a Maoist attack on the office seven years ago. The office has also sped up work to sort out the information that was lost along with the documents during the Maoist attack.

Meanwhile in Tikapur, freed former Kamaiyas have threatened fresh phase-wise agitation if the government did not heed their problems within five days.

A gathering of the former Kamaiyas here on Friday decided to go for the agitation if their demands were not met. Their demands include right to live in where they are currently living, guarantee of employment, and free health and education.

Due to lack of proper rehabilitation, many Kamaiyas have settled in by encroaching upon various forests in Kailali. Some of the land encroached by the former Kamaiyas include land of Tikapur Multiple Campus, Janata Secondary School and Tikapur airport.

Though earlier they had been saying that they encroached the forests and public land to press the government to meet their demands, the former Kamaiyas have now started demanding right to live in the encroached land.

Though the government of Sher Bahadur Deuba liberated the Kamaiya’s some eight years ago, their problem are getting more and more complex by the day due to the lack of timely arrangement for their rehabilitation.

Source :

Thursday, June 12, 2008

Earth loses weight

American scientists have discovered that the Earth is lighter than previously thought.

Their calculations suggest our planet weighs in at 5.972 sextillion tonnes - that is 5,972 followed by 18 zeros. This new weight is about 10 billion, billion tonnes less than the best previous estimates.

The researchers from the University of Washington arrived at the new value by using a more precise measurement of Isaac Newton's gravitational constant - one of the fundamental quantities in physics.

Affectionately known as Big G, the constant tells us how much gravitational force acts between two masses separated by a known distance.

Like the other fundamental constants such as Planck's constant and the speed of light, Big G is hugely important. It is a necessary ingredient in determining the mass not only of the Earth but also of the Moon, the Sun and the other planets.

Big G crisis

It is absolutely vital to know the numerical values of all the fundamental constants with high accuracy if we are to get a true, quantitative description of the physical universe.

But whereas the values of the other constants have got ever more precise, Big G has experienced a crisis.

"Gravity is the most important large-scale interaction in the Universe, there's no doubt about it," says Jens Gundlach, who with Stephen Merkowitz announced the new mass for the Earth at a meeting of the American Physical Society in Long Beach, California.

"It is largely responsible for the fate of the Universe, yet it is relatively little understood."

Attempts to measure Big G in the 1990s brought results widely different from the previously accepted figure. This prompted the US National Institute of Standards committee which establishes the accepted value to determine that there was actually 12 times more uncertainty about the figure last year than in 1987.

Huge embarrassment

"That is a huge embarrassment for modern physics, where we think we know everything so well and other constants are defined to many, many digits," Gundlach says.

If accepted, the measurement by Gundlach and Merkowitz would reduce the uncertainty by nearly a factor of 100 from the currently accepted figure, making it far more precise than even the 1987 figure.

Gundlach says his numbers could change as additional data are analysed in preparation for submitting the work for peer review.

To make their measurements, the researchers are using a device called a torsion balance. This records nearly imperceptible accelerations from the gravitational effects of four eight-kilogram stainless steel balls on a gold-coated Pyrex plate about the size of a matchbox but just 1.5 millimetres thick.

The device, operating inside an old cyclotron hall in the UW nuclear physics laboratory, is similar to one used 200 years ago to make the first Big G measurement. But it is computer controlled and contains numerous mechanical refinements that make the more precise measurement possible.


Wednesday, June 11, 2008

Flood warning issued as China's main "quake lake"nears drainage point

The possibility of flooding from the Tangjiashan "quake lake," caused by China's May 12 earthquake, increased Thursday even as water levels rose steadily to the point where engineers believe they may be able to open a drainage sluice.

The water level at Tangjiashan Lake in Beichuan County, Mianyang City, southwestern Sichuan Province, had risen to 738.81 meters by 5 p.m. on Thursday, 0.9 meters higher than that of 5 p.m. Wednesday. It was still 1.19 meters below the drainage sluice, according to the lake control headquarters.

The Sichuan Provincial Meteorology Bureau had forecasted thurderstorm for the next two days. The rainfall on Tangjiashan Lake was likely to reach 15 mm to 35 mm, according to the forecast.

Five rescue venues, each with one or two boats, were set up in Jiangyou City in the lower reaches of the lake. Traffic control has been imposed since Thursday afternoon in many townships of the city to keep people within the safe area.

Premier Wen Jiabao arrived in Mianyang Thursday afternoon to oversee drainage of the Tangjiashan Lake by helicopter.

"Now is a critical moment for the Tangjiashan quake lake, and the most important thing is to ensure there are no casualties," he said.

Emergency teams had been hoping to drain the lake on Thursday, but unforeseen factors, such as fresh landslides and higher than expected rainfall, had added to the risk of the lake breaching its banks and flooding downstream areas, said a spokesman with the lake control headquarters.

The mud and rock dam -- caused by a landslide on the Jianjiang River -- was also in danger of collapsing under the pressure of the mounting volume of water behind it. Seepage was already occurring, said the spokesman.

More than 600 armed police and soldiers dug a 475-meter channel to divert water from the lake.

It was expected the lake, which holds more than 200 million cubic meters of water, would start draining as soon as the water level reached the lowest point of the dam.

But a headquarters spokesman warned late on Wednesday the chances of bursting were increasing due to uncertainties. These included aftershocks, rain on the upper reaches and the instability of the mud and rock dam.

"Water has been seeping out of the dam body," he said.

A massive landslide could occur at any time on the upper reaches, which could bring about 20 million cubic meters of mud and rock into the lake, triggering huge waves.

"We must prepare for dealing with the worst scenario, but strive for the best results," said Chen Lei, Minister of Water Resources, at a meeting Wednesday in Sichuan.

He said managed drainage was necessary to "ensure the safety of people downstream."

It was not clear when the draining would start.
More than 250,000 people in Mianyang have been relocated under a plan based on the event that a third of the lake water breaches its banks.

Two other plans required the relocation of 1.2 million people if half the lake volume was released or 1.3 million if the barrier fully opened.

The timing of the drainage must be decided by water inflow, said ministry chief engineer Liu Ning.

The catchment area of the upper reaches covered 3,350 sq km. It was estimated that 2 mm of rain in that area would raise the lake level by 1 meter.

According to weather records, average rainfall in the Tangjiashan area in June stands at 140 mm, in July at 360 mm and in August at 330 mm. Rainfall of such levels would pose grave danger.

Another 10,441 residents in a low-lying area about 50 km from the lake were evacuated on Thursday afternoon, and a traffic ban was enforced in downstream areas. More than 250,000 people have been relocated.

Emergency workers were also searching for residents who were missed in the evacuation.

The May 12 quake triggered massive landslides in Sichuan, blocking the flow of rivers and creating more than 30 unstable "quake-formed lakes" that threatened millions of people downstream.

The 8.0-magnitude quake centered on Wenchuan County, about 100 km southwest of Beichuan, has left more than 69,000 people dead, about 18,000 missing and millions homeless. More than 10,000 aftershocks have been reported since May 12.

An aftershock measuring 5.0 on the Richter scale jolted Sichuan's Qingchuan County at 12:41 p.m. on Thursday, according to the China Earthquake Administration.

Source :

Tuesday, June 10, 2008

ChinaSat-9 Successfully Propelled Into Orbit

ChinaSat-9 has been launched into orbit — otherwise known as ZhongXing-9 (ZX-9), the satellite was carried aloft by a CZ-3B Chang Zeng-3B (CZ3B-10 launch vehicle from the LC2 launch complex at the XiChang Launch Center. ChinaSat-9 will be operated by China Direct Broadcast Satellite Company, Limited, and the manufacturer is Thales Alenia Space, with the satellite based on the company's Spacebus-4000C2 platform. This satellite is a integral component of China's 1G DBS system. With 22 Ku- (18 36 MHz + four 54 MHz) band transponders, the orbital slot for ChinaSat-9 is at 92.2° E. ChinaSat-9 uses the ABS-S (Advanced Broadcast System-Satellite) technology that offers a 30 percent boost on the bandwidth efficiency of the transponder. The new Chinese satellite has a life expectancy of 15 years and will be able to broadcast to approximately 98 percent of the population of China, to include Hong Kong, Macao, as well as Taiwan. China Direct Broadcast Satellite is also planning to launch their Xinnuo-4 (Sinosat-4) and Xinnuo-6 (Sinosat-6) satellites by the year 2010. As you may recall, a 8.0 magnitude earthquake struck the Sichuan province in China on May 12th—fortunately, the XiChang Satellite Launch Center avoided damage, which allowed the launch to proceed.

Jason-2 Launch Postponed

  Jason-2's launch has been postponed by Eumetsat. No longer will this ocean altimetry satellite be boosted into orbit on June 15th, as originally scheduled. The reason for the delay revolves around weather related problems integrating the spacecraft with the Delta II launch vehicle. Plus, adding to the delay dilemma, is NASA's slippage of their GLAST launch, which uses the same type of launcher, ground crews, and set-up procedures. The launch date for Jason-2 is now planned to be no earlier than June 19th. A solid date will be announced and confirmed shortly

Source :

Hunger in Ethiopia now spreading to adults

SHASHAMANE, Ethiopia - Like so many other victims of Ethiopia's hunger crisis, Usheto Beriso weighs just half of what he should. He is always cold and swaddled in a blanket. His limbs are stick-thin. ADVERTISEMENT

But Usheto is not the typical face of Ethiopia's chronic food problems, the scrawny baby or the ailing toddler. At age 55, he is among a growing number of adults and older children — traditionally less-vulnerable groups — who have been stricken by severe hunger due to poor rains and recent crop failure in southern Ethiopia, health workers say.

"To see adults in this condition, it's a very serious situation," Mieke Steenssens, a volunteer nurse with Doctors Without Borders, told The Associated Press as she registered the 5-foot-4 Usheto's weight at just 73 pounds.

Aid groups say the older victims suggest there is an escalation in the crisis in Ethiopia, a country that drew international attention in 1984 when a famine compounded by communist policies killed 1 million people.

This year's crisis, brought on by a countrywide drought and skyrocketing global food prices, is far less severe. But while figures for how many adults and older children are affected are not available, at least four aid groups interviewed by the AP said they noticed a troubling increase.

"Older children are starting to show the signs of malnutrition when normally they might be able to withstand shocks to the system," she added. "What's particularly concerning is that the moderately malnourished are soaring. It's increasing so much that it means those children are going to slide into severe malnutrition."

Ethiopia is not alone in suffering through the worldwide food crisis, which is threatening to push the number of hungry people in the world toward 1 billion. Last week, a U.N. summit of 181 countries pledged to reduce trade barriers and boost agricultural production to combat rising food prices.

But in Ethiopia, food production is hampered by drought, meaning the country has been hit with a double blow. Drought is especially disastrous in Ethiopia because more than 80 percent of people live off the land. Agriculture drives the economy, accounting for half of all domestic production and 85 percent of exports.

Sending more food is one solution, but there already is a global crunch as rising fuel prices drive up the cost of fertilizers, farm vehicle use and transport of food to market. Biofuels, which are made from crops such as sugar cane and corn, are another contentious issue, with critics saying they compete with food crops.

The problem is echoed across Africa, from Kenya and Somalia and farther west. Exacerbating the global rise in food prices, which has sparked protests and riots in several West African nations, is an annual decline in food reserves across the high desert-like region called the Sahel, just below the Sahara Desert.

The so-called "lean season" that begins around June is marked by near-empty grain stores, with the next harvest not due until around September. Locust invasions and poor rains in recent years have only worsened the condition, which leads to deadly malnutrition among young children.

Aid agencies in Ethiopia are issuing desperate appeals for donor funding, saying emergency intervention is not enough. Ethiopia receives more food aid than nearly every other country in the world, most of it from the United States, which has provided $300 million in emergency assistance to relief agencies in the past year.

But despite the international help, the country is again facing hunger on a mass scale. Part of the reason, according to John Holmes, the top U.N. humanitarian official, is the country's climate, chronic drought and the large population of 78 million people.

"The World Food Program feeds some 8 million people already, together with the others in Ethiopia," he said. "But we may need to increase that, because of drought."

The U.N. children's agency has characterized this year's food shortage — in which an estimated 4.5 million people are in need of emergency food aid — as the worst since 2003, when droughts led 13.2 million people to seek such aid. In 2000, more than 10 million needed emergency food.

Studies by the International Medical Corps in southern Ethiopia — the epicenter of the crisis — show that up to one in four young mothers is showing signs of moderate malnutrition.

Ethiopia's top disaster response official, Simon Mechale, insists that the food situation is "under control" and will be resolved within four months. But in the countryside, there are signs that drought has taken a more serious toll.

At a recent food distribution in a village some 155 miles southwest of the capital, more than 4,000 people showed up for free wheat and cooking oil, but only 1,300 rations were available.

Harried health workers picked through the impatient crowd, sorting out the sickest children. Frantic mothers proffered their withered infants, hoping the children's poor state would earn some food for the family.

Villagers said they simply cannot afford the food on the market. The few mature ears of corn in the market were selling for about 11 cents an ear. Last year, when the rains were good, that money would buy six or seven ears.

"I am not able to walk, even," Ukume said. "I walk for one kilometer and I have to rest.

Smog and Acid Rain

Particularly for large metropolitan cities, smog and poor air quality is a pressing environmental problem. Smog primarily consists of carbon monoxide, nitrogen oxides, volatile organic compounds chemically interacting with heat from sunlight forming ground level ozone. Smog is that familiar haze most commonly found surrounding large cities, particularly in the summer time. Smog and ground level ozone contribute to all kinds of respiratory problems ranging from temporary discomfort, asthma, to long-lasting, permanent lung damage. The pollutants in smog come from vehicle emissions, smokestack emissions, paints, and solvents - most of which started out as crude oil.
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Sunday, June 8, 2008




General Background

The synoptic character of Landsat and other large-area coverage satellite remote sensors is proving especially favorable in geologic mapping and other geologic applications. Land cover/use, agriculture, urban monitoring, and similar non-geologic activities related to human endeavors for the most part relate to areal coverage at smaller scales. Geologic phenomena typically are spread over wider scenes, so that the ability to see the "regional picture" is a powerful attribute of space imagery.
This view is somewhat tempered by the "interference" of vegetative cover in trying to single out geologic features. Aerial photography and space imagery work especially well on geologic subjects when the scenes they portray are minimally covered with vegetation. Early spring pictures are usually optimal (before leafing). Also, best results obtain when rocks are exposed (outcrop), are covered with little soil or are bare, and are not buried by alluvial deposits. The best images seen in this Section are in the western United States and arid regions elsewhere in the world.

Geologists have used aerial photographs for decades to serve as databases from which they can do the following:

1. Pick out rock units (stratigraphy)

2. Study the expression and modes of the origin of landforms (geomorphology)

3. Determine the structural arrangements of disturbed strata (folds and faults)

4. Evaluate dynamic changes from natural events (e.g., floods; volcanic eruptions)

5. Seek surface clues (such as alteration and other signs of mineralization) to subsurface deposits of ore minerals, oil and gas, and groundwater.

6. Function as a visual base on which a geologic map is drawn either directly or on a transparent overlay.

With the advent of space imagery, geoscientists now can extend that use in three important ways:

1) The advantage of large area or synoptic coverage allows them to examine in single scenes (or in mosaics) the geological portrayal of Earth on a regional basis

2) The ability to analyze multispectral bands (especially hyperspectral data sets) quantitatively in terms of numbers (DNs) permits them to apply special computer processing routines to discern and enhance certain compositional properties of Earth materials

3) The capability of merging different types of remote sensing products (e.g., reflectance images with radar or with thermal imagery) or combining these with topographic elevation data and with other kinds of information bases (e.g., thematic maps; geophysical measurements and chemical sampling surveys) enables new solutions to determining interrelations among various natural properties of earth phenomena.

While these new space-driven approaches have not yet revolutionized the ways in which geoscientists conduct their field studies, they have proven to be indispensable techniques for improving the geologic mapping process and carrying out practical exploration for mineral and energy resources on a grand scale.

The very first practical use of ERTS-1 (Landsat-1) imagery in any discipline was the drawing by Dr. Paul D. Lowman, Jr, of a geologic structures map superimposed on the first color composite image, based in part on already known field information and in part on his interpretation of this scene. He is a geologist at Goddard Space Flight Center, and an expert on space photography (he prepared Section 12 on Astronaut Imagery in this Tutorial). The image was of the central California coast around Monterey Bay, acquired 3 days after launch.

This map confirmed predictions from his studies of astronauts' photos that Landsat would be an efficient tool for recognizing faults and other known structural trends in small-scale imagery. In spite of lower resolutions, these images excel in portraying regional geologic settings and are easily enhanced by digital processing.

We now consider several examples of geologic applications using these new approaches. We concentrate initially on how Landsat Thematic Mapper (TM) data for a local region in Utah are manipulated to identify different rock types, map them over a large area using supervised classification, and correlate their spatial patterns with independent information on their structural arrangement. Next, our focus changes to examination of geologic structures, particularly lineaments, as displayed in regional settings in the U.S., Canada, and Africa. Then, in Section 5, we will look at how space-acquired data fit into current methods of exploring for mineral and hydrocarbon deposits by considering a case study of a mineralized zone in Utah and at a large-area Landsat scene in Oklahoma. In Section 17, we will return to a geologic theme by examining landforms at regional scales, (so-called Mega-geomorphology), as a prime example in considering how remote sensing is used in basic science studies.

Most geologic maps are also stratigraphic maps, that is, they record the location and identities of sequences of rock types according to their relative ages. The fundamental rock unit is the formation (abbreviated as Fm or fm), defined simply as a distinct mappable set of related rocks (usually sedimentary) that has a specific geographic distribution. A formation typically is characterized by one or two dominant types of rock materials.

The term "formation" is most commonly associated with strata, namely layers of sediments that have hardened into sedimentary rocks. Under most conditions, sediments are laid down in horizontal or nearly so layers on sea floors, lake bottoms, and transiently in river beds. Here is a typical set of sedimentary layers exposed in a road cut (note that the layers have been cut and slightly offset by a break which is termed a "fault"):

If we see sedimentary rocks inclined at more than a few degrees from the horizontal, we should suspect that these are involved in displacements from their original horizontal state by forces (tectonic) that cause the rocks to bend and curve (folds) or break (faults). Here is a roadcut along a Maryland highway that is passing through the fold belt of the Appalachians.

As we shall see later in this Section, inclined layers can produce curved structures called anticlines (uparched) and synclines (downwarched), Here is an example of the latter:

Any given formation is developed and emplaced over some finite span of geologic time. We can approximate its age by the fossils (evidence of past life) that were incorporated within the soft layers (which become strata or beds) during the time in which these life forms existed. Age dating by determining the amounts of radioactive elements and their decay-daughter products can usually produce even more accurate age estimates. Another, less precise, approach to fixing the age (span) of a rock unit is to note its position in the sequence of other rock units, some of whose ages are independently known. We can correlate the units with equivalent ones mapped elsewhere that have had their ages worked out. This method tends to bracket the time in which the sedimentary formation was deposited but erosional influences may lead to uncertainties. The association of sedimentary layers with specific time intervals constitutes the field of stratigraphy. Igneous and metamorphic rocks also have time significance and are treated as rock units on geologic maps (which show all stratigraphic and crystalline units in a legend).

Remote-sensing displays, whether they are aerial photos, space-acquired images, or classification maps, show the surface distribution of the multiple formations usually present and, under appropriate conditions, the type(s) of rocks in the formations. The formations show patterns that depend on their proximity to the surface, their extent over the surveyed area, their relative thicknesses, their structural attitude (horizontal or inclined layers), and their degree of erosion. Experienced geologists can recognize some rock types just by their appearance in the photo/image. They identify others types from their spectral signatures. Over the spectral range covered by the Landsat TM bands, the types and ages of rocks show distinct variations at specific wavelengths. This is evident in the following spectral plots showing laboratory-determined curves obtained by a reflectance spectrometer for a group of diverse sedimentary rocks (collected from their field formations [named from a geographic locality near where the fromationas unit was first described) from Wyoming:

2-1 From these spectra, predict the general color of these four rock units: Niobrara Fm; Chugwater Fm; Frontier Fm; Thermopolis Fm. ANSWER

2-2: What spectrally distinguishes the Mowry Fm from the Thermopolis Fm (both dark in the field); the Jelm Fm from the White River Conglomerate? ANSWER

Several of these spectral signatures are composite, in that more than one mineral substance is present. Spectra of individual minerals can be quite different, as shown in the next illustration:

The Near-IR wavelength interval from 2.0 to 2.4 µm is especially sensitive to absorption of radiation; note that all four minerals share a negative peak (trough) around 2.32 µm. But a word of caution: there are several thousand mineral species known from Earth. The spectra of many of these can be similar, making field and even laboratory distinction of just what mineral species is being looked at difficult to assess (X-ray diffraction patterns are usually better identifiers). When remote sensing is involved in onsite surveys, knowledge beforehand of the particular minerals likely in the sensed scene is usually a benefit. Thus, when an area is being surveyed for specific mineral content (as in exploration for ore minerals; Section 5), this information aids in identifying the mineral species being mapped. This is also true for rock types; whenever possible, field spectra such as shown above for Wyoming formations are gathered as Ground Truth (Section 13) so that their diagnostic characteristics can be used to calibrate the image analysis (as an example, referring to the rock spectra above, the averaged reflectances of the 6 non-thermal TM bands can be calculated for, say, the Muddy Sandstone; this knowledge could then be fed into a computer classification as a discriminator function which looks for all pixels with similar multiband values).

A common way of mapping formation distribution is to rely on training sites at locations within the photo/image. Geologists identify the rocks by consulting area maps or by visiting specific sites in the field. They then extrapolate the rocks' appearance photographically or by their spectral properties across the photo or image to locate the units in the areas beyond the training sites (in effect, the supervised classification approach).

In doing geologic mapping from imagery, we know that formations are not necessarily exposed everywhere. Instead they may be covered with soil or vegetation. In drawing a map, a geologist learns to extrapolate surface exposures to underneath covered areas, making logical deductions as to which hidden units are likely to occur below the surface. In working with imagery alone, these deductions may prove difficult and are a source of potential error. Also, rock ages are not directly determined from spectral data - only material types are determined, so that identifying a particular formation requires some independent information (knowledge of a region's rock types and their sequence).

In exceptional instances, such as those to be shown on the next three pages, when geologic strata are turned on their side (from folding; discussed on page 2-5) so that the successive geologic units are visible as a sequence, the changes within and between each discrete unit can be measured in terms of some spectral property, as for example, variations in the reflectance of a given band, or a ratio of bands. When plotted as shown below the result are tracings that resemble (analogously) those made from well logging of such properties as electric resistivity, permeability, magnetic intensity and other geophysical parameters. Here are two figures, the top showing the succession of sedimentary strata exposed along the Casper Arch in central Wyoming; the bottom being reflectance "logs" derived from spectral traverses along one of the lines in the upper image:


In the lower diagram, the bottom unit is the Permian Phosphoria Formation, extending upward from the Triassic Chugwater Formation to the Frontier sandstone (Cretaceous) at the top. On the right the left tracing is of TM Band 3 (red), with 0% reflectance on the right base extending to 70% on the left, and the right tracing, for Band 1, goes from 0% on the left to 50% on the right.

Before looking at some specific examples of the use of space imagery for geologic structure analysis, this is a good point to introduce one particular advantage of having space observing systems that can repetitively cover the same large regions over the four seasons. Two Landsat images appear below: one taken during the southern Winter in South Africa; the other during the height of Spring. The area includes Johannesburg, some of the gold mines in the Witwatersrand district, and the Pilanesburg pluton (near the top). In the wintertime, some of the underlying rock units fail to show distinctly because the entire scene has its vegetation (mostly grasslands) dormant. But with plant reawakening in Spring, different units have different vegetation types and these variably modify the colors displayed, thus revealing the more complex structures in the region.

This geobotanical phenomenon (the differential distribution of various plant types as a function of soils developed on different rock types) is sometimes used as a mapping or prospecting device (example; the element Selenium is associated with Uranium; certain plants thrive on Selenium enrichment and are thus indicators of subsurface Uranium enrichment).


Saturday, June 7, 2008


Seafood is any sea animal or seaweed that is served as food or is suitable for eating, particularly seawater animals, such as fish and shellfish (including mollusks and crustaceans). By extension, in North America although not generally in the United Kingdom, the term seafood is also applied to similar animals from fresh water and all edible aquatic animals are collectively referred to as seafood.

Edible seaweeds are also seafood, and are widely eaten around the world. See the category of sea vegetables.

The harvesting of seafood is known as fishing and the cultivation of seafood is known as aquaculture, mariculture, or simply fish farming.

Seafood is a source of protein in many diets around the world.
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Radar and Microwave Remote Sensing: How Radar Works

How Radar Works

A typical radar system consists of the following components:

(1) A pulse generator that discharges timed pulses of microwave/radio energy

(2) A transmitter

(3) A duplexer that alternates the signals involved between transmitted and received

(4) A directional antenna that shapes and focuses each pulse into a stream

(5) The same antenna which picks up returned pulses and sends them to a receiver that determines the time delays between their transmission and return, and converts (and amplifies) them into video signals

(6) A recording device which stores them for later processing

(7) An electronic signal processing system that analyzes the signal and prepares it for display

(8) A realtime analog display on a cathode ray tube (CRT), or a TVlike monitor, or on film exposed by a moving light beam to record the image.

Each pulse lasts only microseconds (typically there are about 1,500 pulses per second). Pulse length–an important factor along with bandwidth in setting the system resolution–is the distance traveled during the pulse generation. The duplexer separates the outgoing and returned pulses (i.e., eliminates their mutual interferences) by blocking reception during transmission and vice versa. The antenna on a ground system is generally a parabolic dish; the dish can rotate (sweep), commonly over a 360° range, or is fixed and looking outward.

Radar antennas on aircraft are usually mounted on the underside of the platform so as to direct their beam to the side of the airplane in a direction normal to the flight path. For aircraft, this mode of operation is implied in the acronym SLAR, for Side Looking Airborne Radar. A real aperture radar system (RAR), also know as brute force radar, operates with an antenna that has a discrete physical length. (Aperture is analogous to Field of View.) For a SLAR radar this is a long (about 5-6 m) antenna, usually shaped as a section of a cylinder wall. This type produces a beam of noncoherent pulses and uses its length to obtain the desired resolution (related to angular beamwidth) in the azimuthal (flight line) direction.

The antennas can be large, although weight especially is a limit to the size put on an airplane. The antenna used in the SIR-C radar system was designed to fit into the cargo bay of its host Space Shuttle. This is the antenna before it was mated to the Shuttle:

So, for many operational setups there is an upper limit to the size of the antenna. But the system spatial resolution is proportional to length of the antenna, thus getting an antenna as long as practical is an objective in designing the radar. A "trick" can increase the effective length, and hence resolution, by simulating a real aperture through electronic means for integrating the pulse echos into a composite signal. This is the approach used by Synthetic Aperture Radar (SAR), which is always associated with moving platforms carrying the system. SAR utilizes both recording and processing techniques to generate a signal that acts as though it has an "apparent" length greater than the antenna itself. At any instant the transmitted beam propagates outward within a fan-shaped plane, perpendicular to the flight line; this amounts to a "broad beam" through which targets components advance. The movement of the antenna, be it on aircraft or spacecraft, is involved in increasing the effective length simulating a real aperture by integrating the pulse echos into a composite signal. Mathematical manipulation, including Fourier Analysis, is needed to handle the pulse stream associated with the forward motion. More information on SAR is found at the Wikipedia website on SAR.
SIR-A, B, C, Radarsat, ERS-1,2, JERS-1, and Envisat are the main examples of space satellites that use SAR.

Another type of radar system is exclusive to conditions in which there is relative motion between platform and target. This system depends on the Doppler effect (apparent frequency shift due to the target’s or the radar-vehicle’s velocity) to determine azimuthal resolution. As most know, when a target is moving towards the observer, and emits a signal such as a sound, the frequency continues to rise as the target moves closer - the sound increases in pitch; movement away lowers the frequency. Doppler radar is used in the so-called Radar Guns used by the police to gauge auto speeds based on the rate of frequency shift; in this case the radar beam is continuous rather than pulsed.

For a SLAR system, there is a Doppler component in the returned beam that results in changing frequencies, which give rise to variations in phase and amplitude in the returned pulses. As coherent pulses transmitted from the radar source reflect from the ground to the advancing platform (aircraft or spacecraft), the target acts as if it were in apparent (relative) motion. The system analyzes the moderated pulses and recombines them to synthesize signals. The radar records these data for later processing by optical (using coherent laser light) or digital correlation methods; Fast Fourier Transform analysis is also applied. More about Doppler radar is provided by Wikipedia.
Main practical advantage over SAR over SLAR
Let us now consider the beam characteristics of a typical radar system, as well as the nature and interpretation of the signal returns, as displayed on film or a monitor. The following illustration describes this process

The aircraft moves forward at some altitude above the terrain in an azimuthal direction, while the pulses spread outward in the range (look) direction. Any line-of-sight from the radar to some ground point within the terrain strip defines the slant range to that point. The distance between the aircraft nadir (directly below) line and any ground target point is its ground range. The ground point closest to the aircraft flight trace, at which sensing begins, is the near range limit; at this distance the pulsed signal has the shortest roundtrip transit time. The pulsed ground point at the greatest distance normal to the flight path fixes the far range; the delay between the instant of pulse release and its return is longest at the far range.

At the radar antenna, the angle between a horizontal plane (essentially, parallel to a level surface) and a given slant range direction is called the depression angle β (Beta) for any point along that directional line (a mnemonic for that is "lowering your head down from staring forward when depressed"). We refer to the complementary angle (measured from a vertical plane) as the look angle (a good mnemonic is to think of looking up from staring at your feet [vertically downward]). The incidence angle at any point within the range is the angle between the radar beam direction (of look) and a line perpendicular (normal) to the surface, which can be inclined at any angle (which varies with slope orientation in non-flat topography). The depression angle decreases outward from near to far range. Pulse travel times increase outward between these limits. The duration of a single pulse determines the resolution at a given slant range. This range resolution is effectively the minimum distance between two reflecting points along the azimuthal direction that the radar can identify as separate, at that range. Range resolution gets poorer outward for a specific pulse duration. Thus the resolution increases (gets better) with increasing depression angles (it’s optimum, close-in).
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Persian rug sells for record $4.45 million at auction

PROVIDENCE, R.I. - A silk Persian rug dating from the 16th century or 17th century has sold for a record $4.45 million at auction, or about $729.87 per square inch.

The rug was sold by Christie's auction house Tuesday on behalf of the Newport Restoration Foundation. It had been expected to fetch up to $1.5 million.

The rug, which measures 7 feet, 7 inches by 5 feet, 7 inches, had been purchased by the late tobacco heiress Doris Duke in 1990. She left it to the foundation when she died.

Elisabeth Parker, head of Christie's rugs and carpets department, says there are only two other known rugs like it. She calls it an "amazing work of art" and says it has an intricate floral design and an unusually large number of colors, at 17.

Christie's says the buyer prefers to remain anonymous.

Thursday, June 5, 2008

Remote Sensing:General Principles For Recognizing Vegetation

Vegetation can be distinguished using remote sensing data from most other (mainly inorganic) materials by virtue of its notable absorption in the red and blue segments of the visible spectrum, its higher green reflectance and, especially, its very strong reflectance in the near-IR. Different types of vegetation show often distinctive variability from one another owing to such parameters as leaf shape and size, overall plant shape, water content, and associated background, e.g., soil types and spacing of the plants (density of vegetative cover within the scene). Even marine/lake vegetation can be detected. Use of remote sensing to monitor crops, in terms of their identity, stage of growth, predicted yields (productivity) and health is a major endeavor. This is an excellent example of the value of multitemporal observations, involvig several looks during the growing season, allows better crop type determination and estimates of output. Vegetation distribution and characteristics in forests and grasslands also are readily determinable.

Planet Earth is distinguished from other Solar System planets by two major categories: Oceans and Land Vegetation. The amount of vegetation within the seas is huge and important in the food chain. But for people the land provides most of the vegetation within the human diet. The primary categories of land vegetation (biomes) and their proportions is shown in this pie chart:

Global maps of vegetation biomes show this general distribution:

Remote sensing has proven a powerful "tool" for assessing the identity, characteristics, and growth potential of most kinds of vegetative matter at several levels (from biomes to individual plants). Vegetation behavior depends on the nature of the vegetation itself, its interactions with solar radiation and other climate factors, and the availability of chemical nutrients and water within the host medium (usually soil, or water in marine environments). A common measure of the status of a given plant, such as a crop used for human consumption, is its potential productivity (one such parameter has units of bushels/acre or tons/hectare, or similar units). Productivity is sensitive to amounts of incoming solar radiation and precipitation (both influence the regional climate), soil chemistry, water retention factors, and plant type. Examine the diagram below to see how these interact, keeping in mind that various remote sensing systems (e.g., meteorological or earth-observing satellites) can provide inputs to productivity estimation:

Because many remote sensing devices operate in the green, red, and near infrared regions of the electromagnetic spectrum, they can discriminate radiation absorption and reflectance properties of vegetation. One special characteristic of vegetation is that leaves, a common manifestation, are partly transparent allowing some of the radiation to pass through (often reaching the ground, which reflects its own signature). The general behavior of incoming and outgoing radiation that acts on a leaf is shown here:

Now, consider this diagram which traces the influence of green leafy material on incoming and reflected radiation.

Absorption centered at about 0.65 µm (visible red) is controlled by chlorophyll pigment in green-leaf chloroplasts that reside in the outer or Palisade leaf. Absorption occurs to a similar extent in the blue. With these colors thus removed from white light, the predominant but diminished reflectance of visible wavelengths is concentrated in the green. Thus, most vegetation has a green-leafy color. There is also strong reflectance between 0.7 and 1.0 µm (near IR) in the spongy mesophyll cells located in the interior or back of a leaf, within which light reflects mainly at cell wall/air space interfaces, much of which emerges as strong reflection rays. The intensity of this reflectance is commonly greater (higher percentage) than from most inorganic materials, so vegetation appears bright in the near-IR wavelengths (which, fortunately, is beyond the response of mammalian eyes). These properties of vegetation account for their tonal signatures on multispectral images: darker tones in the blue and, especially red, bands, somewhat lighter in the green band, and notably light in the near-IR bands (maximum in Landsat's Multispectral Scanner Bands 6 and 7 and Thematic Mapper Band 4 and SPOT's Band 3).

Identifying vegetation in remote-sensing images depends on several plant characteristics. For instance, in general, deciduous leaves tend to be more reflective than evergreen needles. Thus, in infrared color composites, the red colors associated with those bands in the 0.7 - 1.1 µm interval are normally richer in hue and brighter from tree leaves than from pine needles.

These spectral variations facilitate fairly precise detecting, identifying and monitoring of vegetation on land surfaces and, in some instances, within the oceans and other water bodies. Thus, we can continually assess changes in forests, grasslands and range, shrublands, crops and orchards, and marine plankton, often at quantitative levels. Because vegetation is the dominant component in most ecosystems, we can use remote sensing from air and space to routinely gather valuable information helpful in characterizing and managing of these organic systems.

The ability to distinguish different types of vegetation was brought home to the writer (NMS) through a simple study using a densitometer to examine multispectral images of a strip of agricultural land near the Choptank River in the eastern shore of Maryland. These images were part of an experiment by my "boss", Dr. Warren Hovis, at Goddard. He had built a multispectral sensor to fly on an aircraft that would simulate images made by the same four bands on the ERTS-1 (Landsat-1) Multispectral Scanner (MSS). Here are the images:

The relative gray levels are plotted as a four band histogram for each of the numbered features in the above image. It should be evident that there are real differences in these band signatures among the vegetation and other features present; thus Mixed Hardwoods have different relative "brightness" patterns from Soybeans, from Old Hay, etc..

This discrimination capability implies that one of the most successful applications of multispectral space imagery is monitoring the state of the world's agricultural production. This application includes identifying and differentiating most of the major crop types: wheat, barley, millet, oats, corn, soybeans, rice, and others.

This capability was convincingly demonstrated by an early ERTS-1 classification of several crop types being grown in Holt County, Nebraska. This pair of image subsets, obtained just weeks after launch, indicates what crops were successfully differentiated; the lower image shows the improvement in distinguishing these types by using data from two different dates of image acquisition:

This is a good point in the discussion to introduce the appearance of large area croplands as they are seen in Landsat images. We illustrate with imagery that covers the two major crop growing areas of the United States.

The first scene is part of the Great or Central Valley of California, specifically the San Joaquin Valley. Agricultural here is primarily associated with such cash crops as barley, alfalfa, sugar beets, beans, tomatoes, cotton, grapes, and peach and walnut trees. In July of 1972 most of these fields are nearing full growth. Irrigation from the Sierra Nevada, whose foothills are in the upper right, compensates for the sparsity or rain in summer months (temperatures can be near 100° F). The eastern Coast Ranges appear at the lower left. The yellow-brown and blue areas flanking the Valley crops are grasslands and chapparal best suited for cattle grazing. The blue areas within the croplands (near the top) are the cities of Stockton and Modesto.

The second Landsat image is in the Wheat Belt of the Great Plains. The image below is of western Kansas in late August. Most of the scene consists of small farms, many of section size (1 square mile). The principal crop is winter wheat which is normally harvested by June. Spring wheat is then planted, along with sorghum, barley, and alfalfa. This scene is transitional, with nearly all of the right side being heavily planted, but the left side (the High Plains, at higher elevations) contains some unplanted farms and cropfree land, some used for grazing.

Still another example of winter wheat in early growth is this scene in southwestern Australia, east of Perth. Some of the wheat fields are quite large - 5 km (3 miles) or more on a side. The prevailing color is tan but with a faint red cast, implying initial growth. There is a sharp line dividing many fields from the mallee scrub (dark brown) growing on soils derived from Precambrian rocks. This line marks an electrified rabbit fence, keeping these "pests" from nibbling on the wheat and other crops being grown.

Many factors combine to cause small to large differences in spectral signatures for the varieties of crops cultivated by man. Generally, we must determine the signature for each crop in a region from representative samples at specific times. However, some crop types have quite similar spectral responses at equivalent growth stages. The differences between crop (plant) types can be fairly small in the Near-Infrared, as shown in these spectral signatures (in which other variables such as soil type, ground moisture, etc. are in effect held constant). In this illustration, the curves have been offset to make it easier to see each plot; if plotted to the same actual values, they would almost superimpose.

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