Orthophoto
An orthophoto is an aerial or satellite image that has been corrected so the scale is the same everywhere. This makes distances on the photo match real distances on the ground and lets the image align with a map projection. Unlike a regular photo, an orthophoto accounts for terrain height, lens distortion, and camera tilt, giving a map‑ready image for use in GIS as a reliable background map.
To make an orthophoto, a digital elevation model (DEM) or topographic map is used to fix distortions caused by varying ground distance from the camera. The result is a georeferenced image that can be placed accurately on a map. Software can add labels or symbols, or automatically create linework such as roads and buildings.
Orthorectification isn’t perfect—tall buildings can still cause errors. If the image uses the highest surface model (DSM) rather than ground elevation (DTM), the product is called a true orthophoto.
An orthophotomosaic is made by stitching several orthophotos together. Google Earth imagery is an orthophoto. An orthophotomap adds map elements like a title, north arrow, scale bar, and legend, and may include other data layers. A spatiomap is a similar concept used for disaster relief.
This page was last edited on 3 February 2026, at 09:59 (CET).