Estimate grid values by triangulation
The GRID TRIANGULATION function allows you to fill the Grid Model by linear triangulation. The function creates a delaunay triangulation of the initial data (similar to a DTM surface), then for each point in the grid finds the triangle that the point is inside and uses linear interpolation on the three triangle vertices to estimate the value at the grid point.
To run this function: Choose Surfaces > Contouring > Estimate grid values > By triangulation, or...
Note: As mentioned above, the Grid Triangulation function creates a delaunay triangulation of the initial data.
This triangulation covers the area of the initial data (in fact, covers an area inside the convex boundary of the initial data) but in general will not encompass the whole grid.
Therefore the Grid Triangulation function will only fill in that portion of the grid which is inside the area of the initial data.
Choose Cancel on the SELECT STRING FILE SOURCE form to return to the GRID menu or Apply to display the TRIANGULATION PARAMETERS form.
Constrain interpolation?
Enter N if you wish to fill the whole grid. Enter Y if you wish to define spatial constraints, eg inside string or above a certain x value, to define a subregion of the grid to be filled in this pass.
Enter Y in the Constrain interpolation? field to display the ENTER CONSTRAINTS form.
Choose Cancel on the TRIANGULATION PARAMETERS form to return to the SELECT STRING FILE SOURCE form or Apply to perform the triangulation interpolation calculations.
Results
Once the calculations are completed the current grid is displayed on the screen as point markers in the graphics layer grid_display. The layer grid_display can be saved to a string file using the SAVE FILE button on the GRID menu. You can also toggle its display using the LAYERS Status button on the GRID menu.
Errors
Invalid D field for point x= xxx y= yyy z= zzz, calculations will continue ignoring this point
Invalid D field found in the initial string data, this point will be ignored.
Insufficient data points present for calculations to proceed
There are not enough initial data points present.