Satellite mapping, geo fencing are important: SC

The Supreme Court has said that Satellite mapping and Geofencing are “extremely important” considering that unauthorised construction is a perennial problem and suggested using these modern technologies.

A bench of Justices Sanjay Kishan Kaul and Abhay S Oka has said that Satellite Mapping of lands and buildings and Geo-Fencing are required to detect encroachments. “It is necessary that the modern technologies for Satellite mapping of lands and buildings to detect encroachments and unauthorized/illegal constructions and Geo fencing of lands/premises for prompt monitoring and control takes place,” the apex court said.

The top court said this last week while hearing cases relating to the de-sealing of properties.

The bench said that on analysis of the matter, it finds that in order to detect encroachment of land, a preliminary requirement was conducting satellite mapping of lands and Digitisation of Cadastral Maps which apparently has already been completed by the Delhi government under Digital India Lands Records Modernisation Programme (DILRMP).

The next requirement is to obtain High-Resolution Satellite Imagery of the area from the Indian Remote Sensing Agency (IRSA) or other external sources such as Google, said the bench.

Getting aerial photographs by engaging services of a drone fitted with high precision cameras also could be an alternative, the bench said, as it’s considered to be superior in quality, as compared to Satellite Imagery pictures.

The next step would be a Geo fencing of the Digitalised Cadastral Maps and High-Resolution Satellite Imagery (of all aerial photography) by fixing reference points along the boundary of the areas selected for Mapping. Such reference points are fixed by using Electronic Total Station (ETS) and Differential Global Positioning System Equipment (DGPS) and the number of such points shall vary, depending on the area to be mapped and the topography, said the court.

Once the aforesaid two exercises are completed, the Geo reference maps are superimposed on each other to obtain changes/variations of ground realities from the Land Revenue records. Proper alignment of the Geo-referenced Digitalised Cadastral Maps and Satellite Imagery/aerial photography after allowing for permissible variations between the two, shall provide the necessary details regarding encroachments, it added.

On the point of unauthorised or illegal construction, the court noted that the development plans of the area are to be mapped which are made available by the Delhi Development Authority (DDA).

The bench said, “Geo reference of the area selected for mapping to detect unauthorized/illegal constructions is to take place in terms of what we have expounded aforesaid and services of a drone fitted with high precision cameras to take 3D pictures of the entire area for the selected survey. The aerial photography obtained from the Drone shall be superimposed on the Geo reference area development plans to detect unauthorised usage of lands for construction within the permissible zone. The aerial photography obtained from the drone needs to be verified individually with the approved building plans by the DDA.”

It said that Geo-Fencing is widely used for various purposes including surveillance and monitoring of selected areas. The technology could ideally be used in cases of water bodies, forests and mines which require regular monitoring to prevent encroachment and illegal mining.

In September, the top court constituted a judicial committee of two retired High Court judges which would deal with the issues relating to sealing and de-sealing of properties, regularisation or levy of penalties or conversion charges, demolition of unauthorised construction, and removal of encroachment.