The following project variables relate to the Impervious Areas variable category. They refer to imported or Heads Up Digitised impervious area polygons in the CatchmentSIM project and also to options selected for the background impervious proportion and method of treatment for overlapping polygons as selected in the Impervious Areas Form.
CatchmentSIM can handle complex multi-region polygons such as island polygons. These polygons are described by multiple vertex sets called regions. For example the complex polygon shown below consists of three regions, the first describes the outer perimeter while the second and third regions describe the internal polygons (ie., areas omitted from the complex polygon surface). Simple polygons have only one region.
These project variables must all be prefixed with %ImperviousAreas.
IMPPolygonsExist |
Returns True if impervious area polygons exist in the current project, otherwise False |
True / False |
|
BackgroundIMPProportion |
The background impervious proportion selected in the Impervious Areas Form |
decimal |
m2/m2 |
OverlappingIMPPolygonsOption |
Returns a description of the method of treatment selected for overlapping impervious area polygons in the Impervious Areas Form |
text |
|
NumberOfIMPPolygons |
The number of impervious area polygons in the project |
integer |
|
IMPPolygon[i].ImperviousProportion |
The impervious proportion of this impervious area polygon 'i' |
decimal |
m2/m2 |
IMPPolygon[i].NumberOfRegions |
The number of regions in this impervious area polygon 'i' |
integer |
|
IMPPolygon[i].Region[j].NoOfVertex |
The number of vertex in this region 'j' in this impervious area polygon 'i' |
integer |
|
IMPPolygon[i].Region[j].Vertex[k].Xcoordinate |
The x co-ordinate of this vertex 'k' in this region 'j' in this impervious area polygon 'i' |
decimal |
|
IMPPolygon[i].Region[j].Vertex[k].Ycoordinate |
The y co-ordinate of this vertex 'k' in this region 'j' in this impervious area polygon 'i' |
decimal |
|
IMPPolygon[i].Region[j].Vertex[k].Easting |
The easting of this vertex 'k' in this region 'j' in this impervious area polygon 'i' |
decimal |
user coordinate |
IMPPolygon[i].Region[j].Vertex[k].Northing |
The northing of this vertex 'k' in this region 'j' in this impervious area polygon 'i' |
decimal |
user coordinate |
IMPPolygon[i].Region[j].Vertex[k].Elevation |
The elevation of this vertex 'k' in this region 'j' in this impervious area polygon 'i' |
decimal |
m |
