When Tata Chemicals wanted to set up a soda ash plant in the Jamnagar area of Gujarat,engineers needed some basic information: where to find limestone, an essential ingiredient in the manufacture of soda ash; potential sources of water, which the manufacturing process required; and the soil condition of the region.

Conventional means of surveying to achieve these objectives would have meant untold hours of field work. Collecting soil and data samples is a tedious and expensive process. The alternative: take a look at the region from above. The company hired Indian Resources information & Management Technologies (IN-RIMT), a Hyderabad-based firm that uses sateflite-generated data to study natural resources and the environment.

IN-RIMT is one of a slew of Indian firms that is making the best of remote sensing, a well -developed but little-used resource, to benefit industry. To the unaided human eye, the earth is a featureless eye in space. But sensors on orbiting satellites can detect not only physical features but all that makes up those features. That's a great help to many. Fishermen along India's coastline have been the beneficiaries of satellite data that have helped them zero in on fish. Cameras on Indian remote-sensing (IRS) satellites do this by sensing the colour, turbidity and flotsam changes in sea water.

For years, IRS satellites of the Department of Space (DoS) have been scanning the subcontinent, compiling voluminous data on the country's features and natural resources. But it's only now that Indian industry is waking up to the potentialoithe remote-sensing programme.

'Remote sensing is a tool that is just beginning to be exploited for a variety of applications,' says D.V Raju, managing director of Susee Spacetek, a manufacturer of electronic equipment used in Remote Sensing. After 24 years with the DoS, Raju, who set up a firm to exploit India's Remote-Sensing capabilities cornmerdafly, should know. 'From siinulators, which test the accuracy of ground station, to equipments that help decode.

signals from satellite cameras, all the equipment that vve manufacture are based on technology transferred from the National Remote Sensing Agency (NRSA),'he says.

Ever since the first remote-sensing satellite, Landsat, was launched by the US in the early seventies, to pan the planet from its orbit and photograph the earth, remote sensing has spawned an industry of its own, which deals only in data and information gleaned from the satellite images. There are two distinct trends in the nascent commercialisation of India's remote-sensing programme. nbere are the spinoff opportunities to set up consultancy and manufacturing units,' says Y.S. Rajan, an advisor in the department of science & technology. The other trend is in the applications, which are growing in a variety of fields: m The National T'hermal Power Corp conunissioned a remote-sensing study, together with conventional means, to gauge pollution of surface water and ground water front a fly-ash pond at the Rarnagundam super thermal station in Andhra Pradesh.

a Feasibility studies for the proposed 12,000 km nationwide Super National ltghway Project will extensively use remote sensing to decide where to build the newhighways.

a Beflary Steels & Alloys in Karnataka used remote-sensing data when officials

wanted to find more water for production; the study found water could be drawn from borewells and a check dam with the plant premises.

M/S Tata Consulting Engineers (TCE) is using it to see if there's enough ground water for the proposed information technology park in Bangalore.

It is time industry realised the utility of remote sensing,' says N. Srinivasan, director at the Confederation of Indian Industry (.CH), which together with the Indian Space Research Organisation (Isro) and the NRSA conducted a seminar to explore how best this could be achieved. One prominent example is the case of Reliance Industries, which was in search of location-specific information for its proposed refinery on the coastal belt of Gujarat. More than the feasibility of the project, the fine needed to know about the refineries envirornnental impact. To do this, scientists first needed to know the region's layout and topography. Then, they needed to study the population spread and vegetation, including forest cover, and ground water supplies. 'We undertook to do it,'says Dr. Subba Rao Pavuluri, IN-RIMT's managing director. 'We study the satellite photographs, interpret them and then carry out field tests to verify the facts. Data from the NRSA can be interpreted according to the client's needs,' says Rao. Though estimates of the current market size are hard to come by, K. Kasturi rangan, chairman of Isro, predicts a 5.1 billion (Rs. 3,100crore) industry for the commercial exploitation of remotesensing data in the next five years.

There are three components to remote sensing: there's the satellite launch vehicle; the remote-sensing satellite that it carties aloft; and then there's the data that this satellite gathers. The first two are is.ro territory, it is the third that holds fascinating possibilities. 'The data and its spinoff technologies have enormous opportunities for entrepreneurial minds," says Rajan.

Remotely-sensed data consists of digital images made up of discrete digital units, which hold the details of an object. They cannot be seen, but they can be handled quantitatively. And it is here that the need for expertise arises. Based on the statistical and interpretative tools applied, these units reveal a lot, for a remotely-sensed hnage is not a photograph in the conventional sense of the word.

The individual picture elements, which are called pixels, have an intensity value, which varies with the electromagnetic radiation that falls on it from the earth's surface. Different objects on the earth's surface reflect these waves in varying degrees of intensity. In doing so vegetation, soil, water, and urban areas stamp their signatures on the sensor.

Electromagnetic radiation can be either in the visible, near-infrared or infrared spectrum of light; it can also be in the thermal and microwave wavebands. Each spectral characteristic discloses something about the object that reflects it. Interpreting data and differentiating between signatures to arrive at useful information calls for expert knowledge.

Interpretation in turn calls for image processing of the discretely gathered pictures. A direct offshoot of analysing remote-sensing data is image processing, the storage of images on computer-compatible tapes, which are fed into a computer for manipulation and finally displayed as an image. Vijav Bhargava, a DeIW-based entrepreneur, says: 'The processing techniques have a lot of other interesting applications.' Bhargava uses image processing for a variety of industrial purposes to extract information not visible to the naked eye. 'About 90% of information today is still on paper,' he says. 'This is the area that is ripe to use electronic docuinent-management svstem and image-processing tectmology.'

Even as small entrepreneurial opportunities continue to present themselves, larger developments on the national and intematioinal scene indicate the importance of that industry attaches to the use of data from the space. One indication is the agreement between Antrix (Isro), the DoS and a US company, EOSAT, to sell data generated by IRS satellites throughout the world.

"It is at the cutting edge of the knowledge-based industries,' says Dr.Rao, describing Remote-Sensing applications. 'From planning the development of the Bangalore metropolitan region, to helping TCE set up a technology park, Remote Sensing is replete with possibilities of all kinds." From thanking the stars, Indian industry could perhaps begin to thank the satellites.