#2606: Bugs in r.sun ----------------------+----------------------------------------------------- Reporter: ojni0001 | Owner: grass-dev@… Type: defect | Status: new Priority: normal | Milestone: Component: Default | Version: unspecified Keywords: | Platform: MSWindows 7 Cpu: x86-64 | ----------------------+----------------------------------------------------- I am new to this, so some things I write here may not be how it should be. My environment: Win7 x64 GRASS Version (7beta and RC1) and hence 32 bit binary (although I mentioned GRASS7, but it may be present in GRASS 6, and earlier versions)
I have 2 issues, probably needs 2 tickets but I am mentioning here both. I used a virtual landscape with elevation = constant (i.e. flat) Issue 1. I found that if I am using the aspect raster, zero degree is East and 270 is South (as mentioned in the help). But if I am using a single value for aspect, zero or 360 degrees is North and 180 degree is South. I don't know if 90 degree is East or West. So, either help document has to be changed or the algorithm. Issue 2. When the slope is more than 60 degrees (probably from 45 degrees) facing North (northwards from east or west and North), the global radiation values are increasing i.e. the radiation value for slope of 70 degrees is more than when the slope is 60 degrees the radiation value for slope of 90 degrees is more than when the slope is 80 degrees Here, is a small table for demonstration (aspect of 0 or 360 is North, as mentioned in issue 1 above) Jan->17 (day=17), Feb->16 (day=47), Mar->16 (day=75) April->15 (day=105), May->15 (day=135) slope aspect Jan Feb Mar Apr May 10 345 1.61 2.45 3.59 5.24 6.52 20 345 0.93 1.73 2.93 4.70 6.18 30 345 0.36 1.04 2.21 4.03 5.67 40 345 0.13 0.46 1.49 3.26 5.01 50 345 0.12 0.15 0.85 2.42 4.22 60 345 0.11 0.16 0.85 2.38 4.17 70 345 0.10 '''0.59 1.63 3.38 5.12''' 80 345 '''0.54 1.29 2.47 4.30 5.94''' 90 345 '''1.20 2.05 3.28 5.11 6.62''' 10 360 1.59 2.42 3.57 5.23 6.52 20 360 0.87 1.66 2.87 4.67 6.17 30 360 0.27 0.91 2.11 3.99 5.66 40 360 0.13 0.26 1.30 3.21 5.00 50 360 0.12 0.14 0.47 2.36 4.21 60 360 0.11 0.13 0.56 2.48 4.35 70 360 '''0.10 0.35 1.51 3.49 5.32 ''' 80 360 '''0.38 1.12 2.42 4.41 6.15 ''' 90 360 '''1.08 1.97 3.28 5.22 6.81''' For testing I have attached a zipped file (simulation for slope 0 to 90, step 10 degrees and for aspect 0 to 360, step 15 degrees) with the script and sample elevation (flat landscape) file. The table may look a bit different but the pattern will be similar. Thank you. Nirmal -- Ticket URL: <http://trac.osgeo.org/grass/ticket/2606> GRASS GIS <http://grass.osgeo.org> _______________________________________________ grass-dev mailing list grass-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-dev