Mapping:Assigning Parameter Values to Individual Grid Cells
As described in the preceding chapters, the simulation of many processes requires that parameter values be assigned to every cell in the active watershed grid. GSSHA can accept parameter values for every cell as a specified uniform value, as a GRASS ASCII map with a different value for every cell, or as tabled values referenced to index maps.
In WMS, parameters are assigned to cells by using the mapping tables and index maps. Index maps are maps that assign integer ID values to every cell in the active watershed area. Index maps for distributed parameters are usually based on soil texture, land use, and vegetation classifications. Parameter values are assigned to each cell based on its index number. A table of parameter values is created for each process and assigned an index map.
- Assigning Parameter Values to Individual Grid Cells