A DEM/Contour is a digital geographic dataset of elevations in xyz coordinates. The terrain elevations for ground positions are sampled at regularly spaced horizontal intervals. DEM/Contours are derived using photogrammetric method using Ground Control Points (GCP) among many other data. GCP acquired by implementing of GPS. The principle behind DGPS is to use the refernce location of the base receiver to correct for the error position of the unknown rover position.
Main objective of work is to Prepared 1/5m interval Contour for project “Nepal Railway Alternative Alignments” from Pleiades stereo-pair satellite of 0.5m resolution.
Digital Terrain Model (DTM) is an important data for the purpose of any terrain related analysis.