On Wed, Jan 28, 2009 at 10:40 AM, Otto Dassau <otto.das...@gmx.de> wrote: > On Tue, 27 Jan 2009 15:46:02 -0800 (PST) > Hamish <hamis...@yahoo.com> wrote: > >> Otto Dassau wrote: >> > I would like to analyse elevation data (slope, aspect, etc) around a >> > point with a defined radius. For my analysis I would like to devide >> > that circle into several sectors 1,5,10,x degree steps, like a pie. >> > >> > Is that possible in GRASS? Are there people who did >> > something similar? Any hints and ideas are welcome. >> >> r.reclass into range bands, then >> d.histogram style=pie (perhaps rendered into a corner sub- d.frame) >> or somehow into a vector DB + 'd.vect.chart ctype=pie' > > thanks for your suggestion, but maybe my description was not very clear. I > would > like to split data into spatial sectors and then start my analysis. E.g.: > > a) Create a 1km buffer around a coordinate > b) Split this circle into sections (subareas) with a certain degree value. If > I > choose 1 degree the circle would be devided into 360 subareas > c) Do my analysis in each sector > > I am thinking about a solution for b)
With v.buffer you can create a circle. Then with a bit of geometry [1] you can calculate the angles and more (perhaps implement in a shell/python script) and then generate the lines and centroids with v.edit. Finally rebuild the topology to obtain sector areas (v.build). Hope this helps, Markus [1] essentially, radius of circle, angle, school geometry :) _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user