[gdal-dev] Algorithm to clip the inner loop of a polygon

[Chao YUE]

Dear all,

Does anyone have some experience or is aware of some algorithm that can
find and clip the inner loop formed in a polygon ? I attach one example
here. In this case I would only keep the outer points and drop the ones
that make an inner loop. I am developing some algorithm to simulate
wildland fire propagation. The algorithm is based on Richards 1990.

In the paper he described an algorithm based on two steps: (1) find the
points where a concave curvature is made. (2) search for both sides of this
point to see where any two line segments cross over each other.
But I am wondering whether there is already some existing solutions or
other better ones.

Thanks a lot for the kind help for any hints on this !
Kind regards,
Chao

Gwynfor Richards, 1990. An elliptical growth model of forest fire fronts
and its numerical solution. International journal for Numerical Methods in
Engineering, Vol. 30, 1163-1179.

[image: InnerLoop.png]

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Chao YUE（岳超）
西北农林科技大学水土保持研究所 研究员
黄土高原土壤侵蚀与旱地农业国家重点实验室
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess
Plateau
Institute of Soil and Water Conservation
Northwest A&F University, Yangling, Shaanxi 712100, P.R. China
chaoyue at ms.iswc.ac.cn
Mobile: +86 18709187546
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