General Settings for the Ground Surface Tool

In this section, we explain general settings for the Ground Surface tool. 

Control input data

These settings control the input data actually used, by providing you with possibilities to overrule the selected elevation input.

NB! Points with unknown elevations will always be omitted. Points with unknown elevations are shown with a blank z-value in the properties pane.

• Use point geometry from objects in Elevation Input - this setting overrules whether to actually use the selected elevation input - or not. If unchecked, it filters out features with point geometry.

• Use points from surface geometry of objects in Elevation Input - this setting overrules whether to actually use the selected elevation input - or not. If unchecked, it filters out features with surface geometry.

• Use points from line geometry of objects in Elevation Input - this setting overrules whether to actually use the selected elevation input - or not. If unchecked, it filters out features with line/curve/polyline geometry.

Use outer boundaries and holes when generating the TIN

• Remove long-edge triangles at edge of model - this setting prevents too inaccurate triangle surfaces to build at the edges. Set the max length to define which triangles are acceptable.

• Outer boundary /Hole

  • Non-destructive. Use 2D geometry from boundary/holes. Keep heights in calculated TIN- this setting uses the 2D geometry (plan projection) to shape the spreading of the surface, making no other alterations of the surface.

  • Destructive. Use 3D geometry from selected boundary/holes. Fit TIN to boundary/holes - this setting uses the 3D geometry to shape the spreading of the surface. The nearest triangles will join the limiting geometry and slightly alter the edges of the surface.

Use TIN breaklines

Optimize breakline input data

Breaklines will form sharp edges in the triangulated structure, and normally this gives a better description of the surface.

This is to decide what to do if breaklines are conflicting:

• Line with highest accuracy - Checks the elevation quality of the conflicting features and uses the breakline with the best quality. The other breakline will still be used, but the conflicting element will be omitted. If the quality is the same, it will omit one arbitrarily.

• Mean value - Calculates the average elevation from the two conflicting breaklines, and adds a point with this elevation in the intersecting point

• Lowest - Finds the lowest elevation of the two conflicting features and adds a point with this elevation at the intersection point

• Highest - Finds the highest elevation of the two conflicting features and adds a point with this elevation at the intersecting point

Optimize TIN structure

• Avoid flat triangles - In certain situations flat triangles are generated and we want to avoid that. Learn more

• Add interpolated fictive points - This method removes flat triangles by adding new points to some edges and splitting the triangles to obtain non-flat triangles. Learn more.

• In narrow valleys, create a continuous fall - This is a flat triangle removal method equivalent to the previous one, but in valleys. Learn more.