Have the same file prefix as the input CDED files. High-resolution files can take some time to generate. Note that this is just a preview of theĬontours, the output files have no color or thickness associated with them. Intermediate are yellow, and minor are green. mp file(s)' button.Ĭontours will be drawn during the contour generation process. mp files directly in DEM2TOPO by clicking the 'Create. Such as SRTM files, setting the refresh rate to 30 minutes or longer may save time overall.Īlternatively, disable the plotting altogether using the checkbox for maximum processing speed. Maps that will be tiled, you will generally want to leave this box unselected. If you want all contours to be closed polygons, select the 'Close Outer Contours' checkbox. This will result in files ~ 10x larger than normal, but may save time. The most degredation from high simplification factors. In dramatically smaller files, but with reduced contour fidelity. Select the simplification factor using the slider. When using the USGS color table,Īreas with elevation less than the threshold will be shown as blue in the bitmap preview. This value too high, as it may cut out areas of coastline. That will force DEM2TOPO to ignore all areas beloe this elevation.
If you are contouring an area with large areas of water, select a sea level threshold value Second column can be an integer or floating point number specifying the elevation of the contour.įor example, the following file will create 2 minor contours, and 1 major contour:Īfter importing a CSV file, the contour spacing entry fields will contain -2, indicating that the Must be an integer indicating whether the contour is major (1), intermediate (2), or minor (3).
The imported file must be an ASCII CSV (comma-separated-values) file with 2 columns. You can also import a list of irregularly spaced contour levels by selecting the 'Import Levels' button. Metric spacing is the default, but imperial units can also be used. Less than 10m (50m in mountainous regions) can result in very large files and long processing The CDED files have 1m vertical resolution (accuracy is another matter), but note that contour spacing Select contour spacing for minor, intermediate, and major contour levels. TheĬolor table for the elevation mapping can be changed using the options menu. If the 'Enable Bitmap' button is selected, bitmaps of the DEM files will be shown. Must have a '.dem' extension, whereas GeoTIFF files from 3DEM must have a '.tif' extension. Select the files that you downloaded by clicking the 'Select DEM Files' button. Select 'continue', and you should see the You should see an IDL splash screen if the program loads properly. var file, and select cancel when DEM2TOPO asksĪlternatively, if you downloaded the RT version, you can start DEM2TOPO by running the dem2topo.exe file. If you want to revert to theĭefault settings, just delete the. If you have installed the IDL Virtual Machine, you can start DEM2TOPO by double-clicking the dem2topo.sav file. Note that the Datum is NAD83 for Canadian maps. CDED files that are compatible with DEM2TOPO are available from GeoGratis.gc.ca, The steps in this process are outlined below:ĭEM2TOPO reads CDED Canadian digital elevation files directly, or GEOTiff files coverted from other sources. img files can then be uploaded to a GPS with SendMap (included in the cGPSMapper mp file or import the ESRI shapes into a program such as GPSMapEdit. In order to upload the contour vectors to a Import ESRI files to GPSMapEdit or EquivalentĬreate an OziExplorer Map or a Printed MapĭEM2TOPO generates elevation contours from CDED or GeoTIFF (written by 3DEM)ĭata, and writes them to an ESRI shapefile or Polish Format.