Horizon profile from binary array
- To: mathgroup at smc.vnet.net
- Subject: [mg101697] Horizon profile from binary array
- From: Gareth Russell <russell at njit.edu>
- Date: Tue, 14 Jul 2009 07:34:17 -0400 (EDT)
Dear Group, I am wondering if anyone has a good insight about the following calculation problem. I have a binary array representing a landscape -- for example, ones might be forest, aranged in many patches, and zeros non-forest. For a given zero pixel, I would like to create a 'horizon profile', analogous to what you would see if you were standing in that pixel of the landscape, rotated 360 degrees, and assessed the distance to the nearest 'one' as you swept through the circle. The result would be a vector of distances in some step size from zero to 360. (The angular step size would need to be quite small, because I would want to be able to pick out isolated pixels in the distance.) Sort of like a radial profile, but with a more complicated set-up than a single closed boundary. This sounds like a computationally intensive problem, which could be an issue as I would ideally like to do it for every 'zero' pixel. (The goal is to use the pixel profiles to create a 'movement field' value at each zero pixel that reflects perception of where the 'one' pixels are. This in turn will be used to direct movement of organisms by directed diffusion.) I can think of a few clunky and slow ways to create the profile, but would appreciate any good ideas. Thanks, Gareth -- Gareth Russell NJIT