VoronoiPlotter is a iPhone/iPad App to create a Voronoi/Delaunay diagram from inputted generating points.

Sample of Voronoi Diagram

Sample of Delaunay Diagram

If a generating point label includes comma or space characters, it is enclosed in " when the data is exported as CSV or text. Enclose it in " in the same way as follows when it is inputted with text editor.

Sample) "Point A", 0, 0 "Point B", 1, 2

The first, this app creates Delaunay triangles from generating points. The next, a Voronoi diagram is generated with dividing the edges of triangle. Here, it will be referred to as a "Inner Voronoi Diagram". With this method, a Voronoi diagram does not have Voronoi cells including point on the outer boundary of Delaunay diagram. Therefore, a wide rectangular region than the inner Voronoi diagram is defined, then Voronoi cells for display are generated with dividing the region with the boundary of inner Voronoi diagram and dividing lines between the most outer generating points.

Originally, areas of these additional cells are infinity because these are open shape. In this case, "Voronoi Cell Area" of "Info" in "Graph" is displayed as "-", and zero is output in CSV or text.

Open Voronoi Cell

When "Vertex" is selected from "Format", vertices of polygons of Voronoi diagram or triangles of Delaunay diagram are exported.

For "Voronoi", "voronoi_vertex" and the number of polygons are described. For "Triangle", "triangle_vertex" and the number of triangles are described. After this line, one shape is described per line. If "Item Index" is ON, a index number is placed at the each header of line.

When "Connectivity" is selected from "Format", node coordinates of polygons of Voronoi diagram or triangles of Delaunay diagram, and connectivities of polygon or triangle are exported.

"voronoi_node" or "node", and the number of nodes are described. After this line, one node coordinate is described per line. If "Item Index" is ON, a index number is placed at the each header of line.

For connectivity, "voronoi_connectivity" or "triangle_connectivity", and the number of shapes are described. After this line, one connectivity is described per line. The index number used in connectivity, is the appeared order in node definitions. If "Item Index" is ON, a index number is placed at the each header of line.

For "Triangle", nodes are always shared with neighbor triangles, and the rotational order of vertices is counterclockwise. Then the triangles can be used as FEM mesh.

For "Voronoi", nodes of open cell are not shared with each other.

The number used for item or connectivity start from 0 or 1. It is depend on the selection of "First Index".

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Please replace [AT] to @.