Contours can be generated from DTM files generated from drone, aerial and satellite stereo data. The contour accuracy and interval output will depend on the type of collection performed. Drone collections can have contours down to 10 cm intervals. For the drones, a downgraded contour interval may work better. Depending on the terrain, a 10 cm contour could be too dense to work visually. Aerial intervals can be down to 30 cm or 1-foot contours. Satellite DTMs can generate 3 meter or 10-foot contours depending on the terrain.