About point 4), you can do it simply adding (v.db.addcol) at the beginning of your job, then insert something like this into the loop:
echo "UPDATE (your_table) SET pixval=(what_you_want_to_upload) WHERE FID=$i" | db.execute Inside "what_you_want_to_upload" you can grab what you want from the r.stats output (i.e. the values range). The pixval column type depends on what kind of information you want to insert. If a value range you set it as string type, or whatelse... 2008/1/18, Nikos Alexandris <[EMAIL PROTECTED]>: > Giovanni, > > thank you for your proposal. > > The link to the FAQ (the one that Jose provided) looks like a solution. > > But your idea is clever as well and I had a similar way in my mind. > > If I got it correct you suggest: > > 1. VectorTargetAreas ~~~v.to.rast (based on unique attribute like cat > or FID~~~> RasterTargetAreas (all pixels of a "TargetArea" have now the > same value > > 2.MASK out everything besides the "TargetAreas" ---looping to create as > many MASKS as the the number of the "TargetAreas" > > 3. For each MASK run r.stats > > 4 (I would also like to have) add the output list(s) as a new table > (column pixval) into the initial VectorTargetAreas (with db.connect, > db.addcol, etc). Let's say for a polygons which covers 20 pixels it > would be like: > > FID - cat - pixval > 1 - 1 - 200 > 2 - 1 - 198 > 3 - 1 - 234 > .. - .. - ..... > 20 - 1 - 765 > > > Is it possible to put all this together? > > > r.stats and output into a new column (pixval) > On Thu, 2008-01-17 at 18:25 +0100, G. Allegri wrote: > > Just a rapid idea. > > You could make just one rasterized map of your polygons and then > > insert in a loop this, giving each pixel a unique category value: > > > > r.mapcalc "MASK = if(raster=$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 > > > > -- > Nikos Alexandris > . > Department of Remote Sensing & Landscape Information Systems > Faculty of Forestry & Environmental Sciences, 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
