Ground Sampling Distance

Ground Sampling Distance (GSD) is a crucial parameter for aerial photography, drone mapping, satellite photography, and remote sensing that represents the true size of the ground corresponding to one image pixel. Usually, the Ground Sampling Distance is given in centimeters or meters per pixel and indicates how high or low the spatial resolution of the image is. The smaller the GSD value is, the smaller the size of ground covered by a pixel is, thus providing higher resolution of the image.

Many parameters affect the GSD, including the camera or sensor resolution, altitude at which the image is taken, focal length of the camera and other image acquisition parameters. In case of drone photogrammetry, the choice of an appropriate GSD becomes important for the creation of orthomosaics, Digital Elevation Models (DEM), Digital Surface Models (DSM), 3D models, and point clouds. Knowledge about Ground Sampling Distance is vital for geospatial experts, surveyors, engineers, and remote sensing professionals.