In aerial photography, the height or altitude from which a photograph is taken.
In ArcGIS 3D Analyst, the height at which a surface, raster, or feature is drawn in a scene. Base height for features and rasters can be set from a surface, such as a DEM, or by using a constant value or expression. Features with z-values stored in their geometry can have their base height set using the z-values. Setting the base heights from a surface is also called draping.