Thanks Barry for your interest in my problem. It is indeed an interesting problem at the same time as a complex one.
I've tried your code and it works for two lakes so far. It's seems like a very good base for what I want to do. I'll modify it a little to speed it up. First by removing the very small lakes, than by changing the loop "for" by a "while" as I just need to find if I can fit or not a rectangle, I don't need the rectangle(s). Here is a example of shape I'm going to apply it to: https://www.dropbox.com/s/24eg0eetm0o6dth/lacs_amerrissables.zip There is already a field telling if you could land of not ("AMERISS") that was found by some old ARCgis coding (ARCinfo and aml, not sure exactly how). It was a consultant that did this code for us a couple of years ago, now we want to transfer to R, explaining why I have this problem now. The code was also using iteration, however not random, on rasterized lakes. I think it would be interesting to compare the result from the 2 techniques. I'm going to try that this afternoon, and let you know the result. Thanks again! Bastien -----Message d'origine----- De : b.rowling...@googlemail.com [mailto:b.rowling...@googlemail.com] De la part de Barry Rowlingson Envoyé : 30 juillet 2012 11:41 À : Ferland-Raymond, Bastien (DIF) Cc : r-sig-geo@r-project.org Objet : Re: [R-sig-Geo] determining suitable lakes for landing On Mon, Jul 30, 2012 at 1:52 PM, Rowlingson, Barry <b.rowling...@lancaster.ac.uk> wrote: >> Anybody have an idea how to place the rectangle and discriminate those lakes? To save pasting masses of code in here, I've put a random rectangle tester in a gist: https://gist.github.com/3207893 that does a stupid brute-force approach of trying random NxM rectangles at random angles all over the polygon until it finds one or gives up. I reckon any polygon that doesn't get a solution after 5000 trials is probably so horrendous that no pilot would want to land there anyway... Barry _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
