|
The overwhelming part of commercial implementations for hydrologic modelling focuses on gridded DTM’s,
rather than TIN’s. Grid-based algorithms are far simpler than their counterparts for TIN’s and gridded DTM’s
from major data producers are widely available. Therefore, only the derivation of hydrological information from
gridded DTM’s is discussed here. We assume that each grid point lies in the center of a raster cell, which it can
be associated with.
Yet TIN’s have a better potential of accurately representing drainage features than
grids, as flow directions are arbitrary. Grids have a rigid sampling structure and merely allow 8 flow directions
(4 cardinal, 4 diagonal). The channels and ridges are forced to the locations of grid points, although they would
rarely pass through them in reality.
TIN’s represent drainage features more accurately. Flow directions can be arbitrary.
|
In grids the flow directions are restricted to the grid points. There are only 8 possible flow directions.
|