Michel~ Thank you for your response, though I have taken a long time to say so. I am coming back to this now, and would like to take you up on your offer to look at your script. I am familiar with python, but I am inexperienced with implementing it within GRASS, so that will be a good challenge.
Please let me know what you think about it, ~Jennifer On Wed, Aug 21, 2013 at 4:18 AM, Michel Wortmann <[email protected]>wrote: > Hi jencor808, > I can only recommend using SRTM for subbasin delineations. We are using it > on a regular basis in our hydrological modelling working group. You'll have > to play around with thresholds a little. I use different thresholds for > different areas of my catchment (eg. in mountainous regions I'd want > smaller subbasins). By masking those areas and run r.watershed several > times, you can vary your thresholds and then patch the different subbasin > rasters back together. As the r.watershed algorithm often leaves small > areas at the edges uncovered, you'll have to fill those before or after > patching, otherwise you'll have holes in your subbasin map. You can also > get rid of small subbasins by converting your subbasin raster into a vector > map and then run > v.clean remove small areas (check manual) > > Hope it helps. I have got a python/GRASS script that is station-based that > does the varying thresholds for you and all the cleaning etc. Let me know > if you'd want to give that a try. > Regards, > Michel > > > On 08/16/2013 06:51 PM, jencor808 wrote: > >> Hello all~ >> >> I'm working with SRTM data and trying to produce watershed maps in >> Honduras. >> For most of the country, the threshold seems to work great at 100000, but >> this is not the case on the shore - those watersheds are neglected likely >> due to their smaller scale. Does anyone have experience merging multiple >> scales? Does this make sense? I'd rather not reduce my threshold or the >> whole country because those watersheds seem too small. >> >> As an aside, what do people think about using SRTM for watershed mapping >> in >> the first place - given it is a surface model and not a DEM. >> >> >> >> >> >> -- >> View this message in context: http://osgeo-org.1560.x6. >> nabble.com/SRTM-r-watershed-at-multiple-scales-tp5072884.html >> Sent from the Grass - Users mailing list archive at Nabble.com. >> _______________________________________________ >> grass-user mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/grass-user >> > >
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