To me this looks like a flooding-related question, i.e. to extract the shore lines of a river if it's water level is raised by 1m or 3m? Maybe (1) extract the raster cells of the elevation map that represents the river channel, (2) then apply r.grow and (3) then r.mapcalc to subtract the grown river channel from the original elevation map. /Johannes
On Sun, Sep 16, 2018 at 5:16 PM Markus Neteler <[email protected]> wrote: > Hi, > > Shane Carey <[email protected]> schrieb am Fr., 14. Sep. 2018, 23:02: > >> Hi All, >> >> Does anyone know is it possible to calculate the elevation above a river >> channel (actual river network that was digitised as opposed to being >> extracted from a DTM) from a DTM and create a polygon from it. >> >> I need to calculate heights of 1m and 3m above a river channel on both >> sides of the channel and create a polygon from it. >> > > This isn't clear to me. Could you elaborate? > > Best > Markus > > > Thanks all. >> >> Le gach dea ghui, >> *Shane Carey* >> *GIS and Data Solutions Consultant* >> _______________________________________________ >> grass-user mailing list >> [email protected] >> https://lists.osgeo.org/mailman/listinfo/grass-user > > _______________________________________________ > grass-user mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/grass-user
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