Creating 3D terain mesh from GPS data
1. Mapping the land surface with the GPS
Using the GPS device in continuous record mode (track mode) you can record as much as your memory can hold. Concentrate on ridges, hollows and other defining points of interest.
NOTE: if you are capturing data over an extended period of time (more than a few hours) then you need to be sure to recalibrate the elevation gauge. As the surrounding air pressure changes due to weather patterns it will affect the readings and your points may get skewed over time.
2. Transfer and manipulate points
Copy the data from the GPS onto your computer using a program such as Easy GPS and export to .gpx file format.
3. Elevation adjustment
If the elevation element of your data is skewed, use the GPS Data tool to adjust track segments if the elevation was not recorded consistently.
4. Create a map
Using Global Mapper tool, create a new map. Import the GPX data as a new layer. You can also overlay screenshots from google earth or some other satellite photographs to help orientate yourself.
5. Generate elevation layer from track data
In the control centre window, right click on the GPX data layer and choose “Create elevation grid from 3d vector data”
6. Set data projection
Go to the projection settings under TOOLS > CONFIGURE > PROJECTION and select UTM as the projection type.
7. Export DXF face mesh
From the file menu choose Export Raster and Elevation Data and then select Export DXF 3D face file
8. Import mesh
You can now use this mesh in a modelling application such as 3D studio max, Archicad or Autocad.