On Tue, Jan 28, 2020 at 12:50 PM Pedro Venâncio <pedrongvenan...@gmail.com> wrote: > > Hi all, > > I was testing r.slope.aspect with the "new" -n flag, also to include -e and -n flags in QGIS Processing, but -n flag is giving aspect values of flat areas as -9998, instead of -9999, when the precision choosed is CELL, and the output data type is CELL.
that seems to be a rounding error, even though float or double should be able to represent -9999 exactly. Should be easy to fix. Markus M > > https://grass.osgeo.org/grass78/manuals/r.slope.aspect.html > > I've tested with GRASS 7.6 (on Linux) and GRASS 7.8.2 (on Windows), both in the GUI and CLI. > > (Tue Jan 28 11:19:40 2020) > r.slope.aspect -e -n --verbose elevation=SRTM_PT_25m@PERMANENT slope=SRTM_PT_25m_Slope_Deg_GRASS aspect=SRTM_PT_25m_Aspect_Std_GRASS precision=CELL > Percent complete... > Elevation products for mapset <PERMANENT> in <SRTM_PT_25m> > Min computed aspect 0.0000, max computed aspect 360.0000 > Aspect raster map <SRTM_PT_25m_Aspect_Std_GRASS> complete > Min computed slope 0.0000, max computed slope 75.2970 > Slope raster map <SRTM_PT_25m_Slope_Deg_GRASS> complete > (Tue Jan 28 11:20:24 2020) Comando terminado (43 sec) > > r.info map=SRTM_PT_25m_Aspect_Std_GRASS@PERMANENT > +----------------------------------------------------------------------------+ > | Map: SRTM_PT_25m_Aspect_Std_GRASS@ Date: Tue Jan 28 11:20:24 2020 | > | Mapset: PERMANENT Login of Creator: PedroVenancio | > | Location: SRTM_PT_25m | > | DataBase: D:\ICNF\Modelos_Combustivel_2018\Landscape_File\grass78 | > | Title: Aspect counterclockwise in degrees from east | > | Timestamp: none | > |----------------------------------------------------------------------------| > | | > | Type of Map: raster Number of Categories: 360 | > | Data Type: CELL | > | Rows: 23200 | > | Columns: 11360 | > | Total Cells: 263552000 | > | Projection: ETRS89 / Portugal TM06 | > | N: 278000 S: -302000 Res: 25 | > | E: 164000 W: -120000 Res: 25 | > | Range of data: min = -9998 max = 360 | > | | > | Data Source: | > | raster elevation file SRTM_PT_25m@PERMANENT | > | | > | | > | Data Description: | > | generated by r.slope.aspect | > | | > | Comments: | > | aspect map elev = SRTM_PT_25m@PERMANENT | > | zfactor = 1.00 | > | min_slope = 0.000000 | > | | > | r.slope.aspect --verbose -e -n elevation="SRTM_PT_25m@PERMANENT" slo\ | > | pe="SRTM_PT_25m_Slope_Deg_GRASS" aspect="SRTM_PT_25m_Aspect_Std_GRAS\ | > | S" format="degrees" precision="CELL" zscale=1.0 min_slope=0.0 | > | | > +----------------------------------------------------------------------------+ > (Tue Jan 28 11:26:09 2020) Comando terminado (0 sec) > > > Using the default precision as FCELL, all goes ok: > > (Tue Jan 28 11:33:08 2020) > r.slope.aspect -e -n --verbose elevation=SRTM_PT_25m@PERMANENT slope=SRTM_PT_25m_Slope_Deg_GRASS_2 aspect=SRTM_PT_25m_Aspect_Std_GRASS_2 > Percent complete... > Elevation products for mapset <PERMANENT> in <SRTM_PT_25m> > Min computed aspect 0.0000, max computed aspect 359.8096 > Aspect raster map <SRTM_PT_25m_Aspect_Std_GRASS_2> complete > Min computed slope 0.0000, max computed slope 75.2970 > Slope raster map <SRTM_PT_25m_Slope_Deg_GRASS_2> complete > (Tue Jan 28 11:34:01 2020) Comando terminado (53 sec) > > (Tue Jan 28 11:34:27 2020) > r.info map=SRTM_PT_25m_Aspect_Std_GRASS_2@PERMANENT > +----------------------------------------------------------------------------+ > | Map: SRTM_PT_25m_Aspect_Std_GRASS_ Date: Tue Jan 28 11:34:01 2020 | > | Mapset: PERMANENT Login of Creator: PedroVenancio | > | Location: SRTM_PT_25m | > | DataBase: D:\ICNF\Modelos_Combustivel_2018\Landscape_File\grass78 | > | Title: Aspect counterclockwise in degrees from east | > | Timestamp: none | > |----------------------------------------------------------------------------| > | | > | Type of Map: raster Number of Categories: 360 | > | Data Type: FCELL | > | Rows: 23200 | > | Columns: 11360 | > | Total Cells: 263552000 | > | Projection: ETRS89 / Portugal TM06 | > | N: 278000 S: -302000 Res: 25 | > | E: 164000 W: -120000 Res: 25 | > | Range of data: min = -9999 max = 359.8097 | > | | > | Data Source: | > | raster elevation file SRTM_PT_25m@PERMANENT | > | | > | | > | Data Description: | > | generated by r.slope.aspect | > | | > | Comments: | > | aspect map elev = SRTM_PT_25m@PERMANENT | > | zfactor = 1.00 | > | min_slope = 0.000000 | > | | > | r.slope.aspect --verbose -e -n elevation="SRTM_PT_25m@PERMANENT" slo\ | > | pe="SRTM_PT_25m_Slope_Deg_GRASS_2" aspect="SRTM_PT_25m_Aspect_Std_GR\ | > | ASS_2" format="degrees" precision="FCELL" zscale=1.0 min_slope=0.0 | > | | > +----------------------------------------------------------------------------+ > (Tue Jan 28 11:34:28 2020) Comando terminado (0 sec) > > > The elevation map I'm using is this one: > https://www.fc.up.pt/pessoas/jagoncal/srtm/SRTM_PT_25m.tif > > As CELL is a 32 bit integer with a range from -2,147,483,647 to +2,147,483,647, -9999 should be fine to conform inside it. > > Another issue I see is in r.info, that is showing the title as > > | Title: Aspect counterclockwise in degrees from east > > which is not correct in this case, as the -n flag was used. > > Could these be bugs? > > Thank you very much. > > Best regards, > Pedro Venâncio > _______________________________________________ > grass-dev mailing list > grass-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-dev
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