Ground elevation grid

A Flood Modeller 2D simulation requires the ground elevation data.

These data are used to determine the path water will take across the floodplain. This is often a Digital Terrain Model (DTM) or Digital Elevation Model (DEM).

The tool now accepts the following formats for topography data:

• ASCII Grid (ASC)
• GeoTIFF (TIF)
• Binary Grid (FLT)
• ESRI Shapefile (SHP)

Note that shapefiles are primarily used to apply additional changes to an existing grid. To use a shapefile to define the entire topography of a model then it would need to be a grid made up of a collection of polygons (i.e. one polygon for each grid square). The solver can accept polylineZ and polygonZ format shapefiles. It uses the following hierarchy: If a shapefile has an attribute table with a populated field entitled "height" or "height1", then these elevation data will always supersede the embedded Z values of the polylineZ/polygonZ.