computed in a relatively quick time. Once the drainage basin data have been computed, geometric modeling parameters can be extracted automatically and entered into a hydrologic model (Nelson et al., 1997).
Digital Elevation Models
Digital terrain models are commonly found as grids, referred to in this document as digital elevation models or DEMs (in other documents DEM data includes TIN data). DEMs are composed of identical square cells arranged in rows and columns, each with a unique value to represent the terrain elevation at that point, as shown in Figure 2.1.
Figure 2.1: DEM Grid Cells