Centre's Svamitva scheme spawns infrastructure for accurate map making

The concluding part of the series on Svamitva looks at CORS, a network of GPS-enabled stations for creating maps in quick time

One major infrastructure backbone that Svamitva, the government’s property card scheme for rural India, is creating are the Continuously Operating Reference Stations (CORS), a network of GPS-enabled stations to get the coordinates for accurate map making.

Just like mobile towers in remote and not-so-remote locations, these stations will help develop a grid based on which maps can be quickly drawn to the lowest of scale with very little effort and cost. CORS has speeded up the process of making error-free maps for Svamitva, vital for swift generation of property cards.

Map making has always been an integral part of any nation’s development journey. As former Surveyor General of India, Lt General Girish Kumar, VSM, (Retd), points out, “Maps are nothing but an accurate representation of the ground on paper and the more accurate it is, the more representative it is,” says Kumar.
 

The British carried out what is now called ‘The Great Trigonometrical Survey (GTS) of India’ in 1802. Among the many accomplishments of the survey were the demarcation of the British territories in the subcontinent and the measurement of the height of the Himalayan peaks — Everest, K2, and Kanchenjunga.
 

The GTS survey had an enormous scientific impact as well, since it was one of the first accurate measurements of a section of an arc of longitude and also measured the geodesic anomaly, which led to the development of the theories of isostasy.
 

However, as the equipment used was primitive, the British established survey stations on hill tops and highlands to get some reference points. If anybody had to do a survey, these stations used a benchmark to conduct it. But the process was time consuming and laborious.
 

In 2005, India adopted GPS-based mapping systems and the country aligned our systems to the global datum.
 

Prior to that the Everest Datum was the reference system to measure the latitude and longitude of any place “But,Everest Datum was not a global system,” says Girish Kumar. 
 

In 2005, a national map policy was promulgated under which all the GTS stations across the country were reconfigured to use GPS systems. But since most of these stations were still on hilltops or at elevated levels, accessing them was difficult and time consuming. 
 

The GPS-enabled GTS stations also developed their own ground control points or GCP library. But the libraries were passive stations and needed to be occupied. The CORS, on the other hand, are active stations which are permanently occupied and communicate with a central control centre without any human interface. Earlier, a person had to physically hold a GPS device for two to six hours to get accurate coordinates, but with CORS, the GPS device is permanently installed as it is in a mobile tower.
 

“Under CORS, four GPS stations at a distance of about 50 km create a virtual reference system which is connected to the central centre. The data processing happens in real time,” explains Girish Kumar, adding that with this system in place, any person with a GPS device can get an accurate position in just two to three minutes.
 

Based on CORS, Svamitva maps have been made with an accuracy of 1:500 scale. This means that a scale of 1mm on paper is equivalent to 500mm on the ground.
 

The CORS can also be used for conducting quick and real time surveys of highway projects, railway projects, checking the alignment of any ongoing development project and so on.
 

“Earlier, if anyone had a piece of land and wanted to sell a part of it they had to get in touch with a patwari to get his land demarcated. This generally takes  days. But with CORS, the same thing can be done in minutes. It also minimises human intervention,” Kumar says CORS helps in cutting down the resources and the manpower required to get accurate positioning for map making. 
 

“The CORS can also monitor tectonic movements as they are not manual and are mostly established on the ground. Revenue departments can use them for land management purposes and others for various developmental projects as well,” said Kumar.

Hence, the CORS system is becoming part of the country’s permanent infrastructure for accurately carrying out all future land measurements.