Dear Valentin Thanks for your through inspection. That part of UK is flat with lots of artificial drains and canals. There is a loop river and also 2 parallel channel. The DTM doesn't look great either and I think streams have not been extracted properly in r.watershed.
Cheers Saber On 26/10/11 21:07, Valentin Wittich wrote: > Hi Saber, > > could you recreate the wrong calculation I've get with the point > (527714, 328638). The point is a little above the connection to the > tributary, could it be that the snap function doesn't work proper? > > V. > > On 10/26/2011 12:08 PM, Saber Razmjooei wrote: >> Valentin >> >> Many thanks for your feed back. >> >> The DTM is quite old (over 20 years) and very coarse (50 metre..but >> grass >> region setting is I think 100 metre). >> >> The reason you don't see the point is that it doesn't use the point >> and it >> uses another one snapped to the stream (r.watershed output). But we >> definitely add something to show the point, either user input or the >> snapped one. >> >> In terms of validation, we have Flood Estimation Handbook which >> unfortunately is not free and using the same DTM in our WPS. For >> copyright >> reasons there is no vector output from FEH either. So you need to create >> screenshots. I don't have a license for it. >> >> There will be more bells and whistles to it (hydrological parameters: >> urban extent, main drain slope, max min elevation, etc). >> >> Cheers >> Saber >> >> >> >>> Nice tool, I like it! >>> >>> Three things came up in my mind when I used it. >>> >>> 1) After I selected a point and press calculate I couldn't see any more >>> the point I selected... >>> >>> 2) It seams like there are some wrong calculation. For example for the >>> randomly chosen point (527714, 328638). And the catchment border could >>> be a little smoother ;) >>> >>> 3) I can only select a visual point, it would be nice to select the >>> point by coordinates... it would be more useful. >>> >>> Did you try to validate your data with a independent dataset? I know >>> from France there exists free hydrological surface catchments shapes >>> over the whole country maybe it possible to make a validation with >>> public DEM-data like SRTM. >>> >>> regards Valentin >>> >>> On Oct 26, 2011 9:27 AM, "Saber Razmjooei"<razmjoo...@faunalia.co.uk >>> <mailto:razmjoo...@faunalia.co.uk>> wrote: >>> >>> Dear list >>> >>> We have developed a Web Processing service for calculating >>> catchment >>> outlines in UK using GRASS and PyWPS: >>> >>> http://www.faunalia.co.uk/catchmentfinder >>> >>> Any feedback is appreciated. >>> >>> Regards >>> Saber >>> >>> >>> _______________________________________________ >>> grass-user mailing list >>> grass-user@lists.osgeo.org<mailto:grass-user@lists.osgeo.org> >>> http://lists.osgeo.org/mailman/listinfo/grass-user >>> >>> >> _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
