Out of bounds

Published : Oct 14, 2000 00:00 IST

Security-related restrictions on geographic data are a necessity, but it is not clear whether there is a one-to-one correspondence between the threat perceptions and the restrictions in place on making available certain types of cartographic dat a for public use.

ACCESS to geographical data, particularly cartographic and topographic data, has been a contentious issue in India for long. With the increased application of computers to handle and manipulate geographical data using Geographic Information System (GIS) technologies, which require digital data, the controversy has deepened. The GIS includes computer software and hardware, spatial data or geographic information and procedures to solve problems or provide solutions.

The importance of geographic information for developmental and infrastructure projects - in land use, urban development, water supply, irrigation, rural electric supply, basic telephone services or highway development - is obvious. Geographical data is a n important component also of scientific research and industrial activity relating to geological formations, landslips, tectonic studies, mineral and oil explorations, coastal and oceanographic studies. For such applications, usually, large-scale topogra phical maps (1: 250,000 and larger) are needed. With the advent of GIS, the corresponding demand for geographic information from industry and the scientific community has grown.

In the context of GIS, the problem has been rendered more complex because restrictions on digital data are more than those with regard to analogue data. GIS conferences have unfailingly slammed the government's policies as anachronistic in an era of adva nced technologies of satellite-based high resolution remote sensed images, when up to one metre resolution is available for civilian use after the launch of the U.S. satellite IKONOS - and hand-held Global Positioning System (GPS) receivers which can mea sure coordinates down to a sub-metre accuracy.

The criticism is mainly directed at the Survey of India (SOI), the 233-year old organisation now under the Department of Science and Technology (DST). The SOI is the primary national mapping agency which produces accurate topographic maps of various scal es based on its survey data to cater to civilian and military needs. The SOI's base maps or "toposheets" of appropriate scale form the basis for value-added maps generated by other data generating agencies such as the Geological Survey of India (GSI), th e Naval Hydrographic Office (NHO) and the National Remote Sensing Agency (NRSA) of the Indian Space Research Organisation (ISRO). The contents of the toposheets, being sensitive in nature and of military value, are under the scrutiny of the Ministry of D efence (MoD), the Ministry of Home Affairs (MoHA) and the Ministry of External Affairs (MEA), and a restriction policy on the dissemination of SOI maps is in place. The policy is guided by security considerations articulated by the military operations (M O) wing of the MoD. By extension, the restrictions on SOI maps would apply to value added maps generated by other government agencies.

The restrictions today are much less than what they were soon after Independence. Till 1950, the policy was basically a continuation of the British policy of restricting all topographic maps for "official use only". "It has been a policy of gradual de-re striction," says Brigadier R.N. Srivastava, Deputy Surveyor-General of the SOI. Even so, the prevalent view among users of the SOI topographic maps is that these de-restrictions are done on an ad hoc basis or at least the rational basis for the policies in force is never apparent and that the current restrictions are still too severe. Data in digitised form is just not available.

The Indian Academy of Sciences (IAS), Bangalore, constituted a panel on Scientific Data of Public Interest a couple of years ago. Headed by Roddam Narasimha, Director of the National Institute of Advanced Studies (NIAS), Bangalore, and a member of the Na tional Security Advisory Board (NSAB), the panel went into the issue of public access to geographical data. The idea is that its recommendations could play a positive role in bringing about reforms in data access policies. The Academy hopes to open up a channel for dialogue with the MoD - what so far seems to have been the most difficult part in the various attempts at policy reforms - through the DST, with which it has an immediate rapport.

The present restrictions are governed by an official order No. F.7(7)/64/D(GS-III) dated April 15, 1968. These amount to large-scale toposheets (that is, on scales 1: 250,000 and more) of about three-fifths of the country being in the restricted zone. Th e restricted zones chiefly constitute border areas of about 50 km inside the country's border. With the 1968 order, publication and distribution of maps of coastal States on the scale 1:1M became possible. In the unrestricted zone, toposheets of scales u p to 1: 25,000 are available in the public domain at a price specified by the SOI. All pre-1947 maps (of restricted and unrestricted zones) too have been derestricted as archival material and are available for reference at the National Archives.

However, the publication and export even of maps of unrestricted zones require approval and security clearance from the MoD, although existing criminal laws can be invoked for improper use or representation of SOI maps. Even the pre-1947 maps of the rest ricted zones are not available for reproduction or research. Any request to access pre-1947 data requires clearance by a committee of the National Archives. However, such maps are likely to be available from foreign sources based on data that the British must have carried.

To access toposheets and data of restricted areas there is a procedure which involves providing detailed information to the SOI on the purpose and manner of use. In the words of Brig. Srivastava, "access to restricted data is on a need-to-know basis, as in the case of developmental projects." According to him, for bona fide applications such as district planning, even 1:25,000 scale toposheets of restricted zones have been provided in some cases after a good deal of user interaction. But the user commun ity, particularly researchers and the GIS industry, maintains that the procedure to gain access to restricted data is cumbersome, time-consuming, complex and opaque.

THAT there is a problem in accessing geographical data was affirmed by V.S. Ramamurthy, Secretary, DST. He said: "The country needs clarity on this issue especially as we move gradually from analogue data and maps to digital data sets." According to him, development schemes like watershed development, on which an enormous amount of money is being spent, have suffered because of the lack of adequate basic data on topography, hydrological characteristics and soil parameters. The observations made by S.V. Srikantia of the Geological Society of India, reflect the general perception of the user community. Based on some arguments, he has called for removing all restrictions on topographic maps after civil and military vital areas (VAs) and vital points (VPs ), which number around 200 on an 1: 50,000 map all over the country, as well as other strategic locations are removed from the SOI maps:

1. Satellite-based remote sensed high resolution imagery has revolutionised map-making. The range and depth of satellite observations with regard to security related aspects is so great that the information contained in 1: 50,000 maps of SOI pales into i nsignificance.

2. The MoD insists on the deletion of coordinates (latitude-longitude) before the publication of thematic maps. Satellite-based GPS can determine accurately the coordinates of any point.

3. The 1:250,000 scale or even larger scale toposheets which are restricted by the SOI on security grounds are available for sale from agencies like the Stanford International Map Centre, London.

4. Digitised data are available from foreign sources and even on the Internet.

So, if high quality data are available from other sources, then why are they not being used? Where is the problem? Apparently maps and data from some of these are very expensive. There is also the question of reliability and accuracy. And the absolute ac curacy with which a given point on the map can be read without compromising on security is the key factor that governs the restrictions.

It is true that maps based on satellite imagery are becoming more and more important. According to NRSA Director D.P. Rao, currently available data of 5.8 m resolution from the Indian Remote Sensing (IRS) satellites can be used to make 1:50,000 scale pro ducts and thematic maps. The mandate of the NRSA is to generate thematic maps for specific applications such as forestry, crop estimation and wasteland mapping. However, the features that a 5.8 m resolution imagery can capture is only 60 per cent of what an SOI map - which is based on extensive ground survey - shows at 1: 50,000 scale. This is because satellite imagery can specify details only at dimensions of 1.5-2 times the pixel size. However, this situation is likely to have changed significantly wi th the recently launched IKONOS-generated 1m resolution data. The height and planimetric accuracy achievable (even in maps based on stereo images) is much less than those available from SOI maps. Also, according to Brig. Srivastava, 1:50,000 SOI toposhee ts are about 30 per cent more detailed than similar maps in the public domain in foreign countries produced by mapping agencies similar to the SOI.

But the accuracy of image products and maps based on remote sensed data depends on the accuracy of their 'geo-coding'. This geo-coding is based on 'ground control points (GCPs)' read off base maps of the SOI that are used to orient and fix the satellite imagery. Accurate ground control data are held confidential by the SOI, and even when restricted maps are released for use, GCP data are not always provided. The GCP data are based on ground survey coupled with certain involved techniques of geodesy.

The base maps and GCP data used by the NRSA for its thematic maps are the SOI's 1: 50,000 maps. With these, the location accuracy that the NRSA thematic maps achieve is, according to D.P. Rao, only about 50 m. The accuracy of maps from foreign sources wi ll be even less because they do not have access to accurate GCP data and usually they are geo-referenced with respect to different 'geodetic datums' whose coordination will be relatively shifted with respect to the SOI's coordinates, which can be even up to a kilometre. Even if higher resolution satellite imagery becomes available - for example, the ISRO's Cartosat to be launched next year will have 2.5 m resolution - the absolute accuracy of any geo-referenced location will be constrained by the accura cy of the underlying base map. However, according to D.P. Rao, where higher scale topomaps are not available, there are techniques to improve the accuracy of IRS products up to 20 m with the help of GCP in high resolution images.

Also, very often foreign-sourced maps, particularly from Britain, are based on pre-Independence maps updated and improved upon by data from satellite imagery. According to Brig. Srivastava, at the basic level these maps would have inherent inaccuracies i ntroduced by the stretching of paper toposheets over time. While these would be geo-referenced with respect to the Everest Spheroid, the location accuracy in pre-Independence maps was not very good. Also, the datum parameters have since undergone changes to define the Revised Everest Spheroid which is in use in India. All these lead to inaccuracies large enough for the MoD not to worry about it. And these differences can be seen when one compares the SOI maps with those from other sources, says Brig. Sr ivastava.

The availability of large-scale geographic data on the Net also appears does not help because scanning or downloading of such images provides only 'raster scan' digital data and not 'vectorised' data (which is necessary for area measuring or other system atic analysis in a GIS application). Although there are software methods to convert 'raster scan' data into 'vectorised' data, Brig. Srivastava points out that these will be inaccurate. Because, besides the inherent limitations of the software and techni ques used, either accurate GCPs and correct projection parameters would not be available to these sources - because they are likely to be based on smaller map scales released by the SOI - or they would be based on a different geodetic datums.

WITH the development of intermediate and long range weapon systems, geodetic problems have become more critical than before. For effective targeting by these, detailed cartographic coverage of areas of strategic importance and geodetic computations betwe en these areas and launch sites, which are often on unrelated datums, have become necessary. Both these requirements necessitate the unification of major geodetic datums. For countries like the U.S., datums of at least continental dimensions have become essential for the geodetic information required for the inertial guidance of Inter-Continental Ballistic Missiles (ICBMs). The best solution is to establish a "single" datum for a large area and adjust local systems to it.

Literature on the subject suggests that while the U.S., in its attempt to establish a global geodetic framework, has established connection to its datum over various large datums, the Indian datum computed on the Everest Spheroid has been one of its weak est links. All SOI toposheets carry marks of the GCPs. The larger the scale, the better is the accuracy with which GCPs can be read. This is one of the reasons why coordinates of some of the locations are not allowed to be indicated. As data on Indian GC Ps become increasingly available, it enables better parametrisation of the Indian datum and hence conversion from one datum to the other.

The GPS-based geodetic data based on selective availability (S/A) signals available to the U.S. military, geo-referenced on WGS-84, is aimed to establish the worldwide geodetic base. But, according to experts, for an external agency to get GPS-based coor dinates across the Indian area is not easy because repeated measurements are needed to remove systematic biases and ionosphere-induced errors. If this gets done in spite of physical security around VAs/VPs and strategic locations, this would amount to es pionage.

WHILE it is thus clear that security-related restrictions on geographic data are a necessity, it is not clear whether there is a one-to-one correspondence between the threat perceptions and the restrictions in place. It seems that a Committee of Secretar ies on Security reviewed the restrictions in 1989 and made recommendations. These included exploring the possibility of "tailor-made" maps for civilian use, single window clearance for restricted maps and aerial photographs and simplifying procedures to access data. However, most of the recommendations have remained unimplemented, according to D.P. Rao. According to the SOI, the recommendations were rejected by the MoD.

The restrictions on digital data appear to be somewhat more curious than those on analogue data and maps. All digital data is restricted and digitisation (for example, by mere scanning of even unrestricted analogue SOI maps) is illegal. This appears to d efy logic. "Why is digitisation being treated differently? How can you stop anyone from putting it in a scanner and digitising?" asks Narasimha. Even Ramamurthy, who should be apprised on the issue, said: "For some unknown reason, an unrestricted toposhe et becomes restricted when it gets digitised." However, according to Brig. Srivastava, once the data on Everest Spheroid GCPs is available n digital form, manipulation becomes easier and the relative accuracy of the GCP coordinates is not lost in value a ddition (which could include strategic locations) or scaling.

The widespread demand for digital data both from government organisations and non-governmental organisations (NGOs) led the Cabinet Secretary to constitute a Technical Group on Map Data Policy in 1997 (TG-MAP) chaired by N. Seshagiri, former director-gen eral of the National Informatics Centre (NIC). The TG-MAP Report was submitted in January 1998. The IT Task Force Report of July 4, 1998, endorsed the recommendations of the TG-MAP Committee. These recommendations were considered by the MoD which resulte d in an Office Memorandum (OM) of July 13, 1998. However, this policy instrument, aimed at facilitating access to digital data, has only resulted in more controversies. The OM says that "all users need not be given all encompassing information" but only "development specific" data. It requires that all value addition to the data be vetted by the SOI and the MoD. Many private enterprises, concerned about the time delay that this complex process could result in, feel that the phrase "value addition" has n ot been defined.

However, there are no guidelines for the memorandum of understanding (MoU) which a private agency has to enter into with any of the nine identified agencies (besides the SOI) which could clarify questions such as value addition.

A committee has been constituted under K. Kasturirangan, chairman, ISRO, to evolve the modalities of digitisation, the formats in which the data will be supplied and the mechanism of dissemination. It appears that availability of data (analogue or digita l) of restricted or unrestricted areas was not a serious problem for government agencies and NGOs working with them. It is the private companies, NGOs and researchers engaged in non-governmental projects who are hampered. They can begin to access digitis ed data only after the modalities are finalised.

It is now hoped that the Kasturirangan Committee would come out with uniform standards for the exchange and sharing of data so that the database in one software environment will be on "talking terms" with that in some other environment. For example, when in the execution of a single national project more than one group could be involved, each working with different software platforms. Such policies and appropriate infrastructure for GIS applications have been evolved in the United States, the United Kin gdom and other countries of Europe. There is a need to establish an enabling policy environment and appropriate infrastructure, proposals for which exist on paper, such as the National Geomatics Centre (NGC) and the National Geographical Digital Data Inf rastructure (NGDDI).

According to Brig. Srivastava, the July 13, 1998, policy change is actually an interim measure before the NGC and the NGDDI take shape. "It provides the leverage to assess the real cartographic data needs of the GIS community," he said. "This may not be an ideal thing but it is a half-way house," observed a Defence Ministry official. However, the sad part is that the move has just got stuck somewhere. Even after two years, the Kasturirangan Committee is yet to come out with its recommendations. This sit uation reflects the level of urgency with which the government, despite all the hype about IT, views the problem that confronts the GIS community, a significant component of the Indian IT industry.

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