Whether Google Earth images can be relied on by the government instead of maps provided by a state-owned space applications institute is being debated in the Gujarat High Court in a case that deals with tribals and forests.
In early 2010, the state Tribal Development Department (TDD) had authorised the use of satellite imagery as second evidence in determining claims under the Forest Rights Act (FRA) of 2006, entrusting the task of acquiring imagery and preparing maps to state-owned Bhaskaracharya Institute of Space Applications and Geo-informatics (BISAG), Gandhinagar.
BISAG soon started providing maps even as the TDD commissioner issued three circulars to hasten the process, urging BISAG to prepare at least 60 maps every day, according to the petition.
The task of marking these Common Plots was to be carried out by the human operators sitting in BISAG office, with no field verification and as such highly error-prone, three tribal rights groups Action Research in Community Health & Development, Rajpipla Social Service Society and Paryavaran Suraksha Samiti said in a petition against the rejection of 1.13 lakh FRA claims (out of 1.56 lakh), although a review has been ordered.
The petition adds the maps were in A4 sizes (later in A3), none had latitude/longitude grids and many of these maps had gross mistakes in marking village boundaries, forest survey numbers and common plots.
The groups said they met a top official and showed him the maps, juxtaposing them with satellite imagery from Google Earth, after which the official instructed BISAG to correct these mistakes and prepare larger A2 size maps with latitude/longitude grids. But the official did not insist on ground verification of the maps.
Again, the groups overlaid the new BISAG maps with GPS-based location identifiers and Google Earth images and found that latitude/longitude grids of important landmarks on the new maps were off the mark by 2 to 10 seconds, i.e. 60 to 300 meters, or even more.
The government has since told the HC that Google Earth is not authentic as well as not authorised by state or central government and it is also highly objectionable to use by the government without the permission of the owner.
In reply, the groups termed the governments claims as totally false and said that Google imagery are very high resolution images made freely available in the public domain.
The last hearing took place on Friday and the matter is now likely to come up for hearing in