The next stage in building a CatchmentSIM project is to import suitable GIS data from a number of supported data formats. If the DEM is to be interpolated from contour and watercourse data then this data may be imported as:
•ArcGIS ShapeFile (*.shp)
•MapInfo Mid/Mif
•MapInfo *.tab
•12d Model *.12da
•AutoCAD *.dxf
•Microstation DGN (v7) files
If the DEM is being imported or sampled, then a wide range of raster formats can be utilised. Sampling of ARC-INFO ASCII NET and 12d TIN (.12da) files is also supported.
Data can also be downloaded from various online data sources.
Importing Contour & Watercourse Data
Importing contour data requires GIS files containing line or polyline contours with non-visual data attached that contains elevation information (GIS >> Contours). Watercourse data need only be in 2D, that is, non-visual data is not required (GIS >> Streams).
Sampling / Importing a DEM
If the source data for the analysis is in the form of an external DEM, this information can either be imported (Create DEM >> Import DEM) or sampled (reading point elevation from the DEM to populate the elevation of blank pixels in a user-defined DEM)(Create DEM >> Raster DEM). Sampling a DEM allows you to re-project the DEM and change the resolution whereas importing a DEM preserves the pixel dimensions and projection exactly.
Sampling of external DEMs can either be undertaken by Create DEM >> Raster DEM or Create DEM >> Download DEM Data for an online source.
More information regarding reprojecting DEMs can be found in the Key Challenges section.
CatchmentSIM supports a wide range of raster DEM file formats. CatchmentSIM supports importing and sampling of the following raster file formats:
•Arc/Info ASCII Grid
•Arc/Info Binary Grid (*.adf)
•AIRSAR Polarimetric
•VTP Binary Terrain (*.bt)
•Military Elevation Data (*.dt0, .dt1, .dt2)
•ESRI HDR (*.hdr)
•GMT Compatible netCDF
•Golden Software Grid
•Grid Exchange File (*.gxf)
•SRTM HGT (*.hgt)
•Japanese DEM (*.mem)
•NED DEM
•USGS ASCII DEM (*.dem)
•USGS SDTS DEM (*.cadt.ddf), and
•Terragen Heightfield.
TIN DEM
A Triangular Irregular Network (TIN) may be sampled to assign elevations to a CatchmentSIM DEM. CatchmentSIM supports ASCII-TIN and 12d TIN formats. You will be asked to define the projection of the TIN, otherwise it will be assumed to be in the same projections as the project.
Importing Other Datasets
CatchmentSIM also allows for a wide range of other GIS data sets to be imported and used in an analysis. These include impervious area polygons GIS >> Impervious Area >> Import Polygons(s)), Hydraulic Controls (Flow Mapping >> Database >> Import Hydraulic Control), Lakes (GIS >> Lakes), Oceans (GIS >> Ocean) as well as displaying external vector or raster (image) GIS files. Grid layers that have been developed using the Raster Calculator can also be displayed.
