Plot Voronoi Cells

Use the Grid and Image > Gridding > Tinning > Plot Voronoi Cells menu option (TINVORONOI GX) to plot the Voronoi cells of a Triangular Irregular Network (TIN) file. Voronoi cells are polygonal zones surrounding each node. Any location inside the zone is closer to its "own" node than to any other node.

Plot Voronoi Cells dialog options

Input TIN file	The name of the TIN file to plot. Script Parameter: TINDB.FILE
Cell edge line colour	The colour in Geosoft RGB format for plotted lines defining the Voronoi cell edges. Script Parameter: TINVORONOI.LINECOLOR
Convex hull line colour	The colour in Geosoft RGB format for lines at the exterior edge of the TIN. Script Parameter: TINVORONOI.EDGECOLOR
Line thickness	Line Thickness in mm. Script Parameter: TINVORONOI.THICKNESS
Clip to convex hull	The full Voronoi cells often extend well beyond the convex hull. This feature will clip them at the exterior edge of the TIN. By default clipping is enabled. Script Parameter: TINVORONOI.CLIP

Voronoi Cells

The Voronoi cells are defined as the regions around each node encompassing all points which are nearest neighbours to that node. It is created by joining the perpendicular bisectors of the lines joining each node. By definition, points along a perpendicular bisector are equidistant to the two nodes defining it, and form the boundary (at least in part) of the Voronoi cells for those two nodes.

The image below shows the Voronoi diagram for a set of 16 nodes.

Each region, or cell, consists of the part of the plane nearest to that node. The cells are unique and can be defined similarly in any dimension (Sambridge, Brown & McQueen 1995).