018] How to Create Elevation Areas, Vectorize Rasters, and Generate TIN Meshes in Global Mapper

Convert terrain data into simplified area polygons or complex 3D triangular meshes (TIN) for advanced spatial analysis.

This tutorial covers advanced context menu functions for elevation layers in Global Mapper. You will learn how to group identical elevation values into area features, vectorize specific raster ranges, and convert Digital Elevation Models (DEM) into high-fidelity Mesh/TIN features for 3D modeling workflows.

We continue exploring the Elevation Layer context menu.

Create Elevation Area Polygons from Equal Values

This function works with both elevation and raster layers. It groups elements with the same values into a single polygon.

Select Layers dialog where the user selects the Elevation layer to operate on
img 1 : "Select Layers" dialog where the user selects the "Elevation" layer to operate on

When you run Create Area Feature from Equal Values..., a list of compatible layers will be displayed. Select the elevation layer and click OK. A detailed setup window will then appear.

Setup Equal-Value Area Creation window showing settings for Layer Description and Elevation Fuzziness
img 2 : "Setup Equal-Value Area Creation" window showing settings for Layer Description and Elevation Fuzziness
Detailed Setup Equal-Value Area Creation options
img 3 : Setup Equal-Value Area Creation

Equal-Value Area Creation Settings

  • Layer Description: Sets the name for the new layer to be created.
  • Value Attribute Name: Sets the attribute name that will store the elevation value for the generated polygons.
  • Set up Allowed Color Fuzziness: This applies to raster layers, which we will cover later.
  • Set up Allowed Elevation Fuzziness: This is specifically for elevation layers.
  • Maximum Match Distance: This defines the acceptable elevation range around each value. For example, if you enter "5", it will group elevation values within a $-5$m to $+5$m range into a single polygon. This means the resulting polygon will represent a 10m elevation range. The smaller this value, the more polygons will be generated.

Enter your settings as shown above and click OK.

Map showing color-coded elevation area polygons (Elevation Areas)
img 4 : Map showing color-coded elevation area polygons (Elevation Areas)

The elevation polygons have been created. Let's look at the information for one of them.

Feature Information window for a selected red polygon showing Perimeter, Area, and Elevation range (105-115)
img 5 : Feature Information

By selecting the Feature Info Tool (Alt+P) and clicking the red polygon in the center, we can see its perimeter, area, and the fact that it encompasses an elevation range from 105m to 115m. This is used when you need a simplified representation of elevation.

Vectorize Elevation Raster Data

While Create Area Feature from Equal Values... creates polygons for all values in a given area, Vectorize Raster allows you to select a specific range and convert it into a polygon.

Vectorize Raster Context Menu
img 6 : Vectorize Raster Context Menu
Selecting the elevation layer to apply Vectorize Raster
img 7 : Selecting the elevation layer to apply "Vectorize Raster"

Upon selecting Vectorize Raster, a setup window appears.

Setup Vectorize window with Start: 100 and End: 110 meters entered
img 8 : "Setup Vectorize" window with "Start: 100" and "End: 110" meters entered

Vectorize Raster Options

  • Layer Description: Enter the name for the new layer.
  • Elevation/Slope: Enter the specific elevation (or slope) range you want to convert into a polygon.
  • Discard Areas Smaller than: Polygons with an area smaller than the specified value will not be created.

Clicking OK will generate a polygon covering only that specific elevation range.

Map showing the resulting polygon for the specified 100m-110m elevation range
img 9 : Map showing the resulting polygon for the specified 100m-110m elevation range

Simple, isn't it? It's worth noting that by changing the shader in Global Mapper, you can also differentiate slope or aspect into polygons using these same methods.

Generate TIN Meshes from DEM Terrain

Global Mapper can create both DEM and TIN simultaneously from digital topographic maps. However, if you have imported a DEM from elsewhere and want to create a TIN, you must convert the DEM to a Mesh.

That function is Create Mesh Features from Terrain.

Create Mesh Features from Terrain menu item
img 10 : Create Mesh Features from Terrain...
Selecting the elevation layer in the Select Layers dialog
img 11 : Selecting the elevation layer in the "Select Layers" dialog

Executing this menu brings up the layer selection window followed by the detailed settings.

Mesh Creation Options window showing Grid Spacing and Texture options
img 12 : "Mesh Creation Options" window showing Grid Spacing and Texture options

Mesh Creation Settings

  • Vertical Units: The unit of measurement (obviously Meters).
  • Mesh Grid Spacing: This determines the resolution. For example, setting it to 40x40m means the elevation layer will be analyzed in 40m segments. Smaller values create more accurate meshes.
  • Texture Options: Determines whether to apply the colors of the current layer to the mesh and how detailed that application should be. Smaller values will apply the original layer's colors more accurately.

Click OK to generate the mesh layer.

Map view showing the generated triangular mesh (TIN) overlaid on the terrain
img 13 : Map view showing the generated triangular mesh (TIN) overlaid on the terrain

Conclusion

The mesh layer (TIN) has been successfully registered. Since the remaining items are not directly related to analysis, I will conclude the elevation layer menus here.

Next, we will explore the menus for raster layers.

That's all for today~

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