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2D Triangulation (Delaunay)

Use this dialog to triangulate surveyed data (points, lines, polygons) and point clouds in an application layer.

Where do I find the dialog?

In the context menu of the terrain model drawing, select Tools - 2D Triangulation (Delaunay)...

Using the dialog

Gemini Terrain uses standard Delaunay triangulation. The function creates a triangulated network and a boundary contour, which is a polygon object with the contour type "boundary contour." If the selection for triangulation includes a polygon, the program will automatically use it as a boundary contour, and only points and lines within the contour will be triangulated.

Settings

  • To include all points in the triangulation, set a small value for Minimum point distance. Points within this value are merged into a single point.

  • Check Use only objects in active layer to remove objects in the selection that are in other layers before triangulation is performed.

  • Break lines that cross each other usually have different elevations at the intersection. With Use elevation at intersection, you can choose between the lowest, highest, or average value.

With the option Report crossing break lines, you can get a temporary marker at the point where two lines cross. This marker disappears at the next screen refresh ([F5]).

Point Clouds

Point clouds contain large amounts of data. In such cases, you can run an iterative triangulation process.

You must specify a cell size for the first iteration and the maximum vertical deviation a point can have relative to the final result. First, a coarse triangulation is performed based on points selected with the specified cell size. Then, each point is checked against the triangulated network. If the vertical distance is greater than the maximum deviation, the point is included and the triangulated network is updated. The process repeats for all points.

Procedure

  1. Select objects in the view or the horizontal list field
  2. Choose Tools - 2D Triangulation (Delaunay)... from the context menu
  3. Check the relevant options
  4. Select the application layer where the result should be placed (the default is the active layer)
  5. Click OK to perform the triangulation

The polygon that defines the boundary of the triangulated network automatically gets the contour type Boundary contour.

You can read more about triangulation in the user documentation.