This feature allows the vehicle to climb or descend to maintain a specified distance above the terrain using SRTM data (aka terrain altitude data) provided by the GCS using a mapping service such as Google maps. To follow terrain data user, have to enable the parameters such as Enable Terrain and Terrain Follow switch. The Terrain enable parameter enable the terrain functionality and generate the Terrain folder in your Flight controller SD Card. Terrain follow parameter enables the terrain mode in RTL and Land mode. User can also set the radius using in Terrain Radius Text box and this radius is used to download the terrain file. When user enables the Follow Terrain Data switch, the GCS will generate and download the terrain file and that file is automatically get uploaded to the SD Card. The file is stored permanently into SD Card. To follow Terrain Data the Follow Terrain Data switch should be enabled, otherwise it won't follow Terrain functionality. Before enable Follow Terrain Data switch user have to select the location of Drone which used to download the terrain file. By enabling all these parameters, the vehicle will follow Terrain Data functionality.