On 07/13/2012 04:02 PM, Jaime Palalane wrote:
Dear qgis users, The units should be the units of the coordinate system. I think that if you want altitudes and lengths in meters, you'll have to project both the raster and the line features to a projected CRS with meters as units. I am also trying to use the r.water.outlet command to define a basin draining to a specific point of a stream in raster format but without success as it gives me back only one cell as the basin and not a combination of cells which could form a real basin. Any tutorial or video in how to use this command? Perhaps the problem is that the outlet point must fall exactly on a stream. There's a trick using v.distance to find a drainage point exactly on the stream, described here: http://www.surfaces.co.il/?p=241 First add two columns to the streams layer: outlet_x, outlet_y. Now use v.distance with your outlet point as the "from" parameter, and the stream as the "to" parameter. Set the upload parameter to "to_x,to_y" and the column parameter to "outlet_x,outlet_y". Now after you run, you should get the X,Y coordinates of a point *on the stream* nearest to your planned outlet point. Use those coordinates in your r.water.outlet command, and you should get the full drainage area. HTH, Micha Saudaçoes! -- Micha Silver GIS Consultant, Arava Development Co. http://www.surfaces.co.il |
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