Editing Topography (section)

===Topological modeling===
[[File:Earth_dry_elevation.stl|thumb|[[STL (file format)|STL 3D model]] of Earth without liquid water with 20× elevation exaggeration]]
A [[geographic information system]] (GIS) can recognize and analyze the spatial relationships that exist within digitally stored spatial data. These topological relationships allow complex spatial [[Model (abstract)|modelling]] and analysis to be performed. Topological relationships between geometric entities traditionally include adjacency (what adjoins what), containment (what encloses what), and proximity (how close something is to something else).
* reconstitute a sight in synthesized images of the ground,
* determine a trajectory of overflight of the ground,
* calculate surfaces or volumes,
* trace topographic profiles,