Inspiration: this post on the JSTS group (with an image - good job on requirements!)
JTS implementation: in the lab
Code: Geometry geom = VariableWidthBuffer.buffer( line, 10, 80 );
Output:
Friday 21 August 2015
SliceGraphs in JEQL
In the interests of increasing blog output, I'm going to experiment with using a terser style in posts where the content is mostly self-explanatory. Sort of an embedded microblog...
Inspiration: original Population Lines print , this plot from the Line Graphs in R blog post:
Data: SEDAC World Population grid, subsampled
JEQL script
Plot:
Wednesday 15 July 2015
Even-distribution Random Point and Polygons in JTS
Recently I fixed the JTS KD-Tree implementation so that it works as advertised with a distance tolerance to provide point snapping. This gives a fast way to produce random point fields with even distribution (i.e. no points too close together).
First, generate a batch of random points using RandomPointsBuilder. As is well known, this produces a very "lumpy" distribution of points:
Using the Concave Hull algorithm available here with the same distance tolerance produces a random polygon with a very pleasing appearance:
First, generate a batch of random points using RandomPointsBuilder. As is well known, this produces a very "lumpy" distribution of points:
Then, put them in a KD-Tree using a snapping distance tolerance. Querying all points in the final tree produces a nice even distribution of points:
Using the Concave Hull algorithm available here with the same distance tolerance produces a random polygon with a very pleasing appearance:
I suspect that these kinds of polygons might be useful for generating stress tests for geometric algorithms.
UPDATE: Adding a bit of Bezier Smoothing produces an even cooler-looking polygon:
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