IntroductionTerrain Navigator Pro can import a wide variety of GIS data as an Overlay or Custom Map (with the optional Sites Add-on) to display over its vast library of maps and images. In order to properly place this information (commonly loaded from in the shapefile or DXF file formats) the Projection (aka Coordinate System) must be specified. However, neither .DXF nor .SHP files (on their own) contain the coordinate system projection that is needed.
Using a .PRJ (projection) FileIn many cases, a .PRJ file will be supplied with the GIS data (shapefile or DXF) which will contain the necessary projection parameters. For example, if you have a GIS_DATA.SHP file, you should also have a GIS_DATA.PRJ file. Often times, these are contained in a single .ZIP archive; extract them into a folder, then open the Layers menu and choose Overlays to import the .SHP file into Terrain Navigator Pro. The .PRJ file, if present, will automatically be detected by Terrain Navigator Pro and used to place the data.
Using a .DC (calibration) FileIn some cases (especially when used in conjunction with Trimble Business Center), a .DC calibration file will be supplied with the GIS data (usually DXF) which will contain the necessary projection parameters. For example, if you have a GIS_DATA.DXF file, you may also have a GIS_DATA.DC file. (Or a .DC file that references the entire dataset.) Open the Layers menu and choose Overlays to import the .DXF file into Terrain Navigator Pro. The .DC file can then be loaded by pressing "Load Projection/Calibration File" in the Choose Coordinate System window.
Picking a Projection/Coordinate SystemIf a .PRJ (or .DC) file is not present in the same directory that matches the root portion of the .SHP or .DXF file, Terrain Navigator Pro will present a list of common map coordinate systems used in North America. Those using the NAD27 datum are presented first, followed by NAD83 and WGS84. State plane, UTM, and degree-based projections are all available.
Select the projection/coordinate system used by your GIS dataset, and Terrain Navigator Pro will properly place the GIS data on its maps. However, if the wrong coordinate system is specified, the data will not be placed properly. Check with the provider of the GIS data for more information about the necessary coordinate system.
My Projection is not shown on the list of available projections. How do I specify less-commonly used Coordinate Systems in Terrain Navigator Pro?
While Terrain Navigator Pro has a fair number of coordinate systems available, there are some that are not currently supported. Fortunately, .PRJ files specify all the necessary information for any projection. Thus, when importing GIS data (from either a .SHP or .DXF file) include a matching .PRJ file that supplies the necessary projection parameters.
.PRJ files for almost any projection/coordinate system can be found at:
In the Choose Coordinate System window, select the US Feet option from the list of available Coordinate Systems, then in "Apply Additional Transformation" choose Feet to Meters. This will apply the correct conversion of units. This can also be used in rare cases where the units in the .DXF file are different than those in the .DC calibration file.
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