On Monday 09 February 2009, Hamish wrote: > buraq wrote: > > I have formatted csv files for every month which is like > > latitude;longitude;turbidityValue. So I want to create > > raster files from these csvs for using in r.sun. > > v.in.ascii -> convert .csv to a vector points file > g.region # set up raster grid > v.surf.rast -> interpolate vector points to raster surface >
Minor correction: v.surf.rast ---> v.surf.rst > > > I have worried about r.sun's Linke Turbidity factor values in areas with > big changes in elevation. Is turbidity value heavily dependent on altitude? > It should, as it is based on a measure of optical thickness (air mass): -------- Extracted from a document ------ m = \frac{1}{sin(\alpha) + 0.15(\alpha + 3.885)^{-1.253}} e^{-0.0001184 \times A} \noindent where $\alpha$ is the solar elevation angle at (12:00 pm local time) on each day of the year, and $A$ is the weather station elevation in meters above mean sea level (MSL). -------- Extracted from a document ------ This stuff is also on pages 40-41 of this document: http://169.237.35.250/~dylan/d_e_beaudette-ms_thesis.pdf Cheers, Dylan > > Hamish > -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user