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Ground Detection

Ground Detection

Owned by Omar Lamrani
Last updated: Mar 06, 2025 by Reza Mahmoudi Kuohi
2 min read

Menu: Analyze / Ground

The Ground Detection tool identifies the lowest points in a point cloud and classifies them as Class 2 (Ground Class), following ASPRS standards.

Additionally, the tool can generate a triangulated surface representing the ground. The precision of this surface is controlled by the minimum cell size, where smaller tiles create finer surfaces but increase processing time.

 

 

1. Ground Detection Settings

Slope Tolerance (in degrees)

  • Defines the maximum surface angle deviation allowed in each cell.

  • Higher values allow rougher surfaces but may introduce more errors in the ground detection.

Minimum Cell Size (in distance units)

  • Determines the precision of the ground surface.

  • Smaller cell sizes increase accuracy but require longer processing times.

  • The cell size must be smaller than the project cell size, or else the project cell size will be used instead.

    • Project cell size information is available in File → Project Info.

2. Processing Area Limitations

Limit by Radius (in distance units)

  • Restricts processing to a circular area centered on a chosen point.

  • Useful for testing different parameter settings or processing small, distinct areas.

Starting Point

  • Defines the initial point for ground detection.

  • Can be:

    • Manually set by entering coordinates.

    • Picked from the point cloud using the "Pick" button.

  • For best performance, select a known ground point to reduce processing time.

  • If Limit by Radius is used, detection will be centered around this point.

Limit by Corridor

  • Processes points along an alignment instead of a circular radius.

  • The corridor settings define the area of points to be processed.

  • Only visible points will be included (hidden points due to class filtering, fences, etc., will be ignored).

3. Ground Classification Settings

Classification (in distance units)

  • Classifies detected ground points as Class 2 (Ground).

  • Elevation Threshold – Defines the maximum vertical distance a point can be from the detected surface to still be considered ground.

Create Surface

  • Generates a triangulated ground surface based on the lowest detected points.

  • The minimum triangle size depends on the Minimum Cell Size setting.

  • The created surface will be available in the Explorer → Object Tab → Surfaces List.

Flatten Outline

  • Flattens the project’s outer boundaries to correct extreme elevation variations.

  • Ensures a smoother transition at project edges without affecting significant points.

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