Hi, You could use focal function on your whole raster with a radius appropriate to your roofs: not too large. raster::focal
You could then use your rasterized roofs as masks then visualize the result raster::rasterize raster::mask plot If you want to go further than just visualizing: Also, for each roof, you could determine different quantiles and determine some areas that are optimal. sp::over or using raster::clump, thus getting one id per roof then calculate quantiles Then why not, polygonizing the result and dissolving: raster::rasterToPolygons maptools::unionSpatialPolygons Best, Mathieu 2012/1/12 didimayr <dieter.m...@boku.ac.at> > Dear all, > > I have a little bit complex problem and don't know how to start solving it. > Maybe someone has experience with similar issues or knows a solution. > > 1) I have many Raster files with (solar-)energy-Values, based on a digital > elevation model (DEM). Depending on the orientation and the slope of cell, > the raster represents the applicability of this field to install a > photovoltaic modul. > 2) Furthermore I have polygons representing the shape of houses (=roof) > lying in the same (raster) area. So the solar-values of the Raster > indicate, > if the house well orientated for a solar module. > > Now I first have to cut the raster with the polygons, in order to analyze > only the roof areas (which are in my interest). > Then comes the main problem: I want to know the energy-value on each roof > (=within each polygon), however it should not only be the sum of the whole > roof, because solarmodules are only situated on the best sites of the roof. > Thus I need to identify a "cluster" or "window" of the highest cell-values > within the polygon, which I want to sum up. If necessary I could define the > size of this window/cluster. > > > It seems to me that I have to work with a focal function or by using RSAGA: > multi.focal.function. > are there other possible approaches and has anyone done a similar analyzis? > > Thanks a lot and kind regards > Dieter Mayr > > > > > > > > -- > View this message in context: > http://r-sig-geo.2731867.n2.nabble.com/summing-up-the-highest-Raster-values-within-polygons-tp7179641p7179641.html > Sent from the R-sig-geo mailing list archive at Nabble.com. > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
