Ground truthing is an essential part of remote sensing based assessment and mapping of forest resources. GT enables linking of image data to the ground reality.
After the change polygons are discerned, doubt points are selected by the analysts on the basis of certain criteria like significant change, mixing of signature and distortion in signature due to radiometry or phenological changes. Around 4000 to 6000 ground truth points are visited by the analysts and State Forest Departments during the FCM cycle. An android based ground truthing mobile application developed by FSI was used for collection, storage and analysis of the information related to ground truthing exercise. Ground data information gathered in the form of geo-tagged photographs, canopy density, tree species and other observations related to change, is stored on the mobile application, and the same was transmitted to the server at FSI head quarter. The data stored in the server was retrieved and used as point GIS layer over the interpreted Forest Cover in order to incorporate changes observed during ground truthing.