Just a rapid idea. You could make just one rasterized map of your polygons and then insert in a loop this, giving each pixel a unique category value:
r.mapcalc "MASK = if(raster=$i,1,null())" with $1 the cat value (deriving from you original polygon) and then run r.stats, which will work only for the un-masked pixels. I don't have time to try this method, hope it helps. GIovanni 2008/1/17, [EMAIL PROTECTED] <[EMAIL PROTECTED]>: > Salut Jose! > > This is what I am doing... and I only have 7 polygons - so > it is ok. > > But if I have 50 polygons... I am not so sure how to script > it to get (finally) a table with all pixels for each unique > polygon for 2 different images of the same location (for > raster MODIS year 2006 and then another of the same area > MODIS 2007!). > > I want to run a regression with the pixel values... (pairs > of 2006 and 2007 values). > > Thank you, > > Nikos. > > > > On Thu, 17 Jan 2008 16:42:31 +0000 > "Jose Gomez-Dans" <[EMAIL PROTECTED]> wrote: > > On Jan 17, 2008 4:30 PM, > > <[EMAIL PROTECTED]> wrote: > > > > > How can I get listed all unique pixel values enclosed > > in > > > each of the polygons I digitised (and for which the > > univ. > > > stats are calculated)? > > > > > > > Can't you just rasterise your polygons, and use that as a > > mask with > > r.mapcalc? You can loop around in your shell. I tend to > > do that with python, > > but it's similar in GRASS. You can also try starspan. > > Or.... < > > http://grass.gdf-hannover.de/wiki/Aggregate_Values> > > > > Cheers, > > Jose > > > > > > > > -- > > Centre for Terrestrial Carbon Dynamics > > Department of Geography, University College London > > Gower Street, London WC1E 6BT, UK > > > . > Nikos Alexandris - Ph.D. Candidate > . > Department of Remote Sensing > and > Landscape Information Systems > (FeLIS) > . > Faculty of Forestry and Natural Environment > Albert-Ludwigs-University Freiburg > . > Tel. +49 (0) 761 203 3697 > Fax. +49 (0) 761 203 3701 > Skype: Nikos.Alexandris > . > Address: Tennenbacher str. 4 > D-79106 Freiburg i. Br. > Germany > . > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
