Forgot to CC grass list On 8/1/07, David Finlayson <[EMAIL PROTECTED]> wrote: > I think you want the command r.statistics. You will need to convert > your administrative areas vector map into a raster map where each area > has a unique ID. Then run r.statistics on the pollution map using the > administrative areas raster as the cover. This tool builds a database > table with the min,max avg, etc statistics of pollution for each area > id. > > > On 8/1/07, George MacKerron <[EMAIL PROTECTED]> wrote: > > Hi all. I've just started out using GRASS, so I hope this question > > isn't too dumb. > > > > I have some raster maps of air pollutant levels in London, by 50m x 50m > > cell. > > > > Firstly, I have a set of postcode points. I have been able to sample > > pollutant levels at these points using v.what.rast. I have also been > > able to sample average and maximum levels within small regions > > surrounding the points (square regions: not ideal, but there we go) > > using r.neighbours (method=average or method=maximum) to produce a new > > raster map, followed by v.what.rast. > > > > However, I also have vector data on administrative areas (such as > > electoral wards), which are up to a few square miles in area, and I am > > trying to discover average and maximum values of the pollutants within > > these areas. I have studied the documentation I can locate, but have > > not been able to work out how to achieve this. > > > > Any help -- or pointers to where I can find relevant tuturials/docs -- > > would be very gratefully received. > > > > All the best, > > George > > > > -- > > George MacKerron > > > > _______________________________________________ > > grassuser mailing list > > [email protected] > > http://grass.itc.it/mailman/listinfo/grassuser > > > > > -- > David Finlayson, Ph.D. > Operational Geologist > > U.S. Geological Survey > Pacific Science Center > 400 Natural Bridges Drive > Santa Cruz, CA 95060, USA > > Tel: 831-427-4757, Fax: 831-427-4748, E-mail: [EMAIL PROTECTED] >
-- David Finlayson, Ph.D. Operational Geologist U.S. Geological Survey Pacific Science Center 400 Natural Bridges Drive Santa Cruz, CA 95060, USA Tel: 831-427-4757, Fax: 831-427-4748, E-mail: [EMAIL PROTECTED] _______________________________________________ grassuser mailing list [email protected] http://grass.itc.it/mailman/listinfo/grassuser
