Conducting DGPS survey and mapping for GNSS Main canal portion in forest area in between KM161.250 and KM203.850 in Cheyyur RF, Seshachalam extension RF and Vathaluru RF of YSR Kadapa district using high precise DGPS instrument including establishing the DGPS points (20 min observation for each point) wages, accommodation including food, vehicle transportation cost, local labour and getting authentication of the DGPS data from the Forest Department