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Digital Terrain Models (DTM)

A Digital Terrain Model (DTM) can be automatically calculated as a self-service by user and viewed in delair.ai. It is especially useful to remove unwanted ground objects from a scene at a quarry or mine site.

The input required are a Digital Surface Model (DSM), along with areas defined to delimit objects above the ground (trees, vehicles or water bodies) in the DSM, that will be removed to build the DTM by interpolation.


DSM
DTM


Example on one small area :


Interpolation areaDSMOutput file

1. Inputs

1.1. Mandatory Inputs

  • DSM: Available after the photogrammetry
  • Interpolation Areas: vector file (DXF, KML, GEOJSON) that delimitates the area to remove.
    This vector file can be an uploaded GEOJSON file. It can also be drawn on the platform with the polygon tool, downloaded as a vector file and uploaded back to the survey.
  • Buffer: Margin outside the Interpolation Area

1.2. Optional Inputs

1.2.1.  3D Ground Points

This is a vector file containing 3D points (x, y, z) that will be used as reference points. These points are used by the algorithm in a manner that is somehow comparable to GCPs for photogrammetry; in certain areas (Interpolation Areas), the model will be "forced" to go through these reference points contained inside interpolation areas.


In other words, inside the interpolation area, the calculated surface will be forced to go through tose 3D Ground Points.


2. DTM Generation

Step 1 - Open your Site in delair.ai, select the appropriate Survey, that must contain a preliminary DSM (issued from a photogrammetry processing in delair.ai, or imported)

Step 2 - Go to the analytics catalog from the analytics button on left bar, and open MINES & AGGREGATES section :

Step 3 - Open DTM and press LAUNCH button :

Step 4 - Select the DSM, plus the Interpolation Areas :

Step 5 - Press Next step button :

Step 6 - Input the Buffer size. If you leave the default value (0) unchanged, you indicate to the algorithm that you do not want to apply any buffer.

Step 7 - Press Launch dtm button, then Finish :


3. Progress & Completion Status

You can check status anytime from the analytic LAUNCHED  tab.

4. Browsing the DTM

Exiting Analytics  section, or from any other section in the platform, follow sequence below :

Step 1 - Go back to Layers section :

Step 2 - Open the BASE LAYERS section and select the DTM :

Step 3 - Clicking on layer will open the information panel on right side; from which you can read the DTM properties, and notably elevation in any point of the map using Value at point tool :


5. Exporting the DTM

In case you need to export for third-party usage :

Step 1 - Go to Downloads section from the left bar :

Step 2 - Select and export your file :

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