triangulation_parameters

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Triangulation Parameters

This dialog box sets parameters for calculating Delaunay Triangulation of Surface Data. The Triangulation is also calculated from this dialog box.

Triangulation is a necessary preliminary step for calculating a Terrain Grid for the Surface. A Terrain Grid is calculated through the Grid Parameters dialog box.

Surface Name

This is the name of the Surface whose Surface Data is to be Triangulated.

Triangulated Region

This provides information on the coordinate range of Surface Data for the chosen surface. The region can be thought of as the smallest rectangle into which all the data will fit in plan view.

Feature Fill Distance

The feature fill distance is the distance between successive points interpolated on a data feature. These interpolated points are used to calculate the triangulation. They form triangle vertices.

The feature fill distance is chosen to prevent "leakage" of triangles through long linear feature segments. It is an alternative to break lines in triangulation.

The default value of feature fill distance is initially set to 5m. It may be a changed through the Terrain/Editor Settings menu item. This opens the Terrain Editor Settings notebook, whose Triangulation page contains the default value.

The initial default value of 5m is chosen to give "safe" triangulation in most practical circumstances. Depending on nearness of other data to features, larger values of feature fill distance (10m or 15m) frequently give acceptable results.

The feature fill distance initially displayed is the default value. If a triangulation has been carried out on the Surface Data, then the displayed feature fill distance is the value used to calculate the triangulation.

Triangulate button

This button calculates Delaunay Triangulation of the Surface Data for the chosen surface.

Close button

This button closes the Triangulation Parameters dialog box.

Next button

This button opens the Grid Parameters dialog box. Calculation of a Terrain Grid is often carried out after triangulation.

A Terrain Grid is calculated through the Grid Parameters dialog box.