DEMs

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A DEM is a Digital Elevation Model. This describes the elevation (height) for a grid of data points – rather like a bitmap or raster. Although elevation data is also sometimes stored as contours or with an arbitrary set of data points, gridded DEMs are by far the most common form of storing and transferring this data. Over the years, a large number of different DEM formats have been used. Maptitude supports a number of common formats, including those in current usage by the USGS. DEM file formats supported by Maptitude include .DEM, .G03, .G98, .DT0, .DT1, .DT2, .FLT, and .ADF files.

USGS Digital Elevation Models can be downloaded from the USGS’s National Map download site.

To import a DEM, simply select File->Open on the main menu, and select the DEM files to open. Maptitude will let you select multiple files (eg. tiles), and they will be imported as one complete DEM. Maptitude will display the Import Digital Elevation Model dialog box:

The Import Digital Elevation Model dialog box. Set the layer name here.

This lets you set the DEM layer’s name (Guadalupe DEM in this example), and also lets you add or remove files. Press OK, and Maptitude will prompt you for the CDF file name that will store the imported DEM data; and then perform the import. Here is the resulting layer:

The imported DEM using the default false color.

This can then be imported into an existing map using the Layers Manager:

The DEM inserted into a map of the Texas-New Mexico border region.

Now the DEM has been loaded, it can be used to create a  surface model.

 

2 comments to DEMs

  • Charlie

    Maptitude has sorrowfully little instruction on how to go from a download DEM Zip folder to an elevation map. Even their tutorial in the User Manual assumes you have your DEM ready to go. Your section helps. Do you know of any Youtube videos that go through the step by step with Maptitude?

  • Charlie

    For example, the smallest DEM that I can isolate for my city is like a 10 x 10 mile block. It is so large, it crashes my system (8 gb ram) when Maptitude tries to process the adf file. There must be a way to get tighter areas from USGS, right?

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