Hi, I'm using GTOPO30 DEM data and TRMM (rainfall) data, I selected the data for the whole of africa but I'm getting an error when executing v.rast.stats.
Here is a step-by-step of what I did: 1. GTOPO30 DEM - downloaded e020n10,w020s10,e020n40,w020n40 compressed files from " ftp://edcftp.cr.usgs.gov/pub/data/gtopo30/global/". - decompressed all the above files. - Added "PIXELTYPE SIGNEDINT" in all .HDR files - warp merged all the .DEM file with "gdalwarp *.DEM Africa.tif" command. - projected it with "gdal_translate -a_srs EPSG:4326 Africa.tif DEM.tif" 2. TRMM "rainfall" data - downloaded 3B42RT.2010061503.1day.tif,3B42RT.2010061503.1day.tfw from "". - projected it with "gdal_translate -a_srs EPSG:4326 -projwin -20 40 60 -60 3B42RT.2010061503.1day.tif TRMM.tif ". Then, imported the two data sets: r.in.gdal in=/home/tgumede1/grassdem/ict4eo/DEM.tif out=dem Projection of input dataset and current location appear to match 100% r.in.gdal complete. Raster map <dem> created. g.region rast=dem r.in.gdal in=/home/tgumede1/grassdem/ict4eo/CapeTown_TRMMs.tif out=rainfall target=CapeTown Projection of input dataset and current location appear to match 100% r.in.gdal complete. Raster map <rainfall> created. r.watershed elevation=dem accumulation=acc drainage=direction stream=str basin=catch memory=300 threshold=100000 SECTION 1a (of 5): Initiating Memory. SECTION 1b (of 5): Determining Offmap Flow. 100% SECTION 2: A * Search. 100% SECTION 3: Accumulating Surface Flow. 100% SECTION 4: Watershed determination. 100% SECTION 5: Closing Maps. 100% Q: How do one really know the exact threshold value? r.to.vect in=catch out=catchments feature=area Extracting areas... 100% 100% Building topology for vector map <catchments>... Registering primitives... 134246 primitives registered 701002 vertices registered Building areas... 100% 44645 areas built 1 isles built Attaching islands... 100% Attaching centroids... 100% Number of nodes: 89602 Number of primitives: 134246 Number of points: 0 Number of lines: 0 Number of boundaries: 89604 Number of centroids: 44642 Number of areas: 44645 Number of isles: 1 Number of areas without centroid: 3 r.to.vect complete. g.region rast=rainfall v.rast.stats vector=catchments raster=rainfall colprefix=precip WARNING: Area without centroid (may be OK for island) WARNING: Area without centroid (may be OK for island) WARNING: Area without centroid (may be OK for island) DBMI-DBF driver error: SQL parser error: syntax error, unexpected NULL_VALUE processing 'NULL' in statement: UPDATE catchments SET precip_cf_=-NULL WHERE cat=17 Error in db_execute_immediate() ERROR: Error while executing: 'UPDATE catchments SET precip_cf_=-NULL WHERE cat=17' - output of r.info -g r.info -g rainfall north=40 south=-60 east=60 west=-20 - output of v.info v.info -g catchments north=40 south=-60 east=60 west=-20 top=0.000000 bottom=0.000000 output of r.info Type of Map: raster Number of Categories: 2559 Data Type: CELL Rows: 400 Columns: 320 Total Cells: 128000 Projection: Latitude-Longitude N: 40N S: 60S Res: 0:15 E: 60E W: 20W Res: 0:15 Range of data: min = 0 max = 2559 Data Description: generated by r.in.gdal Comments: r.in.gdal input="/home/tgumede1/grassdem/ict4eo/CapeTown_TRMMs.tif" \ output="rainfall" target="CapeTown" - output of r.univar r.univar rainfall 100% total null and non-null cells: 115200000 total null cells: 0 Of the non-null cells: ---------------------- n: 115200000 minimum: 0 maximum: 2559 range: 2559 mean: 22.4897 mean of absolute values: 22.4897 standard deviation: 83.1312 variance: 6910.79 variation coefficient: 369.642 % sum: 2590809300 -- Kind Regards TS Gumede CSIR, Meraka Institute 072 258 1650
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