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Magazine
Mapping it right
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India's strength lies in the development of rural and urban areas, improved agricultural productivity and infrastructure. For all this, data on and maps of the earth in an accurate form and intensity are required. The conclusion of a two-part article by L.R.A. NARAYAN.
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A GMS satellite photo that shows smoke plumes (yellow arrows) over the Tasman Sea from the recent forest fires burning around Sydney, Australia.
DATA received from aerial and satellite platforms is used to prepare topographical maps. These maps are geographically accurate and in accordance with international standards. (An elaborate account of the procedures used in map making was dealt with in the first article.) However, it takes a few years to produce them. It is here that satellite data is useful.
Restrictions: The Government has the copyright on all topographical maps. Those wanting to produce such maps have to get the approval of the Survey of India and the Defence Ministry.
Maps that are larger in scale than 1:4 million, must also be submitted to the Ministry of Defence for approval after printing and before publishing, even if it contains only part of the external boundary or coastline. There are many agencies, both private and public, doing research, development activities and superimposing other data, including natural resources information. To publish or make copies they have to get clearance from the Survey of India, and this could take anything from three to six months. This long wait just for clearance for a map can be a hindrance, especially for the scientific community.
Another problem is that some national series of maps on scales such as 1:25000, 1:50000 and 1.250,000 are not made available to all, particularly to the private parties even on payment. Such sheets, falling within 50 kms. from the shoreline, and which form the external boundary with a neighbouring country are classified "restricted" and can be sold or be made available only to authorised government departments or agencies, that too only to an official at Secretary level or department head. If, however, a private individual or organisation were to want it should get the Defence Ministry's permission. Again, those having such maps will have to submit an annual certificate of safe custody to the Survey of India.
The question often asked is how far are such restrictions relevant. Anyone can get satellite remote sensing data. Prior to Independence, our maps were freely available in the U.K. and other countries and even now people abroad get the maps but they might not have been updated for information content. Export of our maps is also prohibited now. How far this can be implemented is questionable.
The following are the main security classification of various documents, maps, aerial photos etc. Top Secret, Secret, Restricted, Confidential and For official use only.
Aerial photographs are also used for interpreting various natural resources, but most aerial photographs are categorised as "secret". Limited aerial photographs have been made freely available for use in schools and universities for teaching purposes. Without clearance from the Ministry of Defence, no organisation can use aerial photographs in India.
Generally satellite remote sensed information is available for a fee from the National Remote Sensing Agency (NRSA), or its authorised agents. However even here certain data such as the Black and White 5.8-metre resolution, at times get partially blocked before being sold to the public, probably at the instance of the Ministry of Defence. With the availability of one metre resolution IKNOS data from the U.S. one can prepare base maps of larger scales of 1:10,000, or even larger, to certain degree of positional accuracy. All ground surveys can also now-a-days be carried out by digital instruments and the data captured could be directly fed into a computer for further processing. The high resolution meter IKNOS like data available outside India are also procurable only through the NRSA and how far one can get these directly is anybody's guess.
In another year or so, the Department of Space plans to launch a CARTOSAT which is to have a ground resolution of 2.5 metres, and with three cameras, one looking forward, one looking directly below and one looking backwards, so that the pictures will have a 3-D possibility. This satellite is to have on board a G.P.S instrument also as in the IKNOS satellite, to get better positional accuracy of the data obtained. This will help easy preparation of maps to be used in GIS analysis.
The recent satellite launched by the Department of Space in India called the Technology Experimental Satellite is expected to give us one meter resolution.
Considering that it is today possible to get a fund of vital information through several means, it is absolutely necessary to have another look at the present policy of "restrictions" and see whether it is possible to relax or how some of the impediments could be removed. This is necessary and the sooner it is done the better. Some commercial companies the world over are trying to come out with even half a metre ground resolution data, which perhaps be able to expose many details on the ground which we falsely, or wrongly, think should not be known to everyone.
Some time ago, topographical maps, of modified specifications, were to be produced by the Survey of India for use as base maps and there was to be no restriction on their availability or use. However, such maps were not produced till now for a number of reasons.
One suggestion is to have a panel of experts that could monitor and bring in practical solutions to improve the present procedures. That will help prevent wrongful use of facilities. One question remains: Can we confidently say that these procedures and restrictions are adhered to by all and is there a foolproof mechanism to monitor any violation effectively, unless someone brings such violations to the notice of the authorities? This may be one of the practical considerations necessitating a close look at the present policies and suggest modifications, in keeping with the changing situations, both in terms of technological considerations and increased and very large number of users. India's growing strength lies in rapid development of rural and urban areas, improved agricultural productivity both in terms of quality and quantity, improved infrastructure including long coastal zones. For all this we need data and maps of the earth in an most accurate form and intensi.
This write up may appear to be rather simple and elementary, but I must emphasise that enlightening general public as well as most users is considered essential. Since most people are aware as to how the various types of data looks like, no attempt is made to include samples of them here. Every citizen has the right to information, but they also have a responsibility to respect various security considerations.
(Concluded)
The first part of this article appeared in the Sunday Magazine, The Hindu, issue dated January 13, 2002 - Getting it right with satellite data
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