Shane Carey wrote > Hi, > > I am trying to extract river network from a 5m DEM with some success using > r.watershed. Has anyone tested this algorithm on high resolution LiDAR > data > for example - 1meter DTM and what kind of results have they obtained?
in the NC sample dateset there is lidar derived 1m x 1m DEM: r.info map=elev_lid792_1m@PERMANENT +----------------------------------------------------------------------------+ | Map: elev_lid792_1m@PERMANENT Date: Wed Feb 14 19:45:24 2007 | | Mapset: PERMANENT Login of Creator: helena | | Location: nc_spm_08_grass7 | | DataBase: D:\grassdata | | Title: Rural area: Lidar-based 1m DEM | | Timestamp: none | |----------------------------------------------------------------------------| | | | Type of Map: raster Number of Categories: 255 | | Data Type: FCELL | | Rows: 750 | | Columns: 700 | | Total Cells: 525000 | | Projection: Lambert Conformal Conic | | N: 220750 S: 220000 Res: 1 | | E: 639000 W: 638300 Res: 1 | | Range of data: min = 103.7643 max = 131.598 | | | | Data Source: | | vector file ncfl_lidar_79200WC_pts | | | | | | Data Description: | | generated by v.surf.rst | | | | Comments: | | giventension=300.000000, smoothing=1.000000 | | dnorm=47.606041, dmin=1.000000, zmult=1.000000 | | segmax=25, npmin=100, rmsdevi=0.222627 | | zmin_data=103.513000, zmax_data=131.668000 | | zmin_int=103.764260, zmax_int=131.598045 | | | | v.surf.rst -t input="ncfl_lidar_79200WC_pts" layer=0 elev="elev_lid7\ | | 9200_1m" slope="slope_1m" aspect="asp_1m" pcurv="pcurv_1m" tcurv="tc\ | | urv_1m" tension=300 smooth=1.0 segmax=25 npmin=100 dmin=1 dmax=2.500\ | | 000 zmult=1.0 | | | +----------------------------------------------------------------------------+ you can test the module with this DEM to see it's appropriate for your need. ----- best regards Helmut -- Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user
