Contour Lines

Contour Lines are defined as lines joining all points of the same elevation on a map. Alteia calculates and displays these lines using a Digital Surface Model (DSM). These lines can notably be used to assess how the terrain is profiled:

1. Generating Contour Lines

Contour lines can be obtained once a photogrammetry process‍ has been completed with an orthomap and a DSM available as layers, or after having imported these inputs processed from third-party software.

Step 1 - Open a Site‍ and select a Survey‍.

Step 2 - Press Analytics button from left panel and select the Contour Line analytics

Step 3 - Select the Elevation Model you wish to use as an input to generate the contour line

Step 4 - Enter the following parameters :

  • DSM Resolution (Default value = 20 cm/px or 1 feet/px) : The GSD value you wish to subsample the DSM. You can find the original GSD of the raster on the info panel. That means you must enter a DSM resolution lower than the original GSD.
  • Minor interval (Default value = 2 m or 5 feet) : Distance between each minor contour line.
  • Major interval (Default value = 10 m or 10 feet) : Distance between each major contour line.
  • Baseline (Default value = 0) : Z value of the starting contour line
  • Smallest area (Default value = 2m² or 50 feet²) : If the contour line enclose an area smaller than this parameter it will be removed from the output

Step 5 - Click on Launch contour lines

2. Displaying Contour Lines

Go to the layer panel and tick your contour lines layer to have it displayed on 2D view. You can adjust some display settings such as the color, by clicking the layer to open its information panel on the right side:
You can change the colour of the contour line by clicking on the vector, go to style section on the info panel and choose “Contour lines light“

3. Exporting Contour Lines

Go to the Download section if you need to export your Contour Lines for further use with a third-party software:

You will be able to choose multiple file formats.

Please click here‍ if wish to learn more about file exportation.