Hi,<br><br>Can anyone help!<br><br><div class="gmail_quote">On Wed, Jul 14, 2010 at 1:31 PM, Sandile Gumede <span dir="ltr"><<a href="mailto:akasandile@gmail.com">akasandile@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Hi,<br><br>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.<br><br>Here is a step-by-step of what I did:<br><br>
1. GTOPO30 DEM<br> - downloaded e020n10,w020s10,e020n40,w020n40 compressed files from "<a href="ftp://edcftp.cr.usgs.gov/pub/data/gtopo30/global/" target="_blank">ftp://edcftp.cr.usgs.gov/pub/data/gtopo30/global/</a>".<br>
- decompressed all the above files.<br> - Added "PIXELTYPE SIGNEDINT" in all .HDR files <br> - warp merged all the .DEM file with "gdalwarp *.DEM Africa.tif" command.<br> - projected it with "gdal_translate -a_srs EPSG:4326 Africa.tif DEM.tif"<br>
<br>2. TRMM "rainfall" data<br> - downloaded 3B42RT.2010061503.1day.tif,3B42RT.2010061503.1day.tfw from "".<br> - projected it with "gdal_translate -a_srs EPSG:4326 -projwin -20 40 60 -60 3B42RT.2010061503.1day.tif TRMM.tif ".<br>
<br>Then, imported the two data sets:<br><br>r.in.gdal in=/home/tgumede1/grassdem/ict4eo/DEM.tif out=dem<div class="im"><br>Projection of input dataset and current location appear to match<br> 100%<br>r.in.gdal complete. Raster map <dem> created.<br>
<br></div>g.region rast=dem<br><br>r.in.gdal in=/home/tgumede1/grassdem/ict4eo/CapeTown_TRMMs.tif out=rainfall target=CapeTown<div class="im"><br>Projection of input dataset and current location appear to match<br> 100%<br>
r.in.gdal complete. Raster map <rainfall> created.<br>
<br></div>r.watershed elevation=dem accumulation=acc drainage=direction stream=str basin=catch memory=300 threshold=100000<div class="im"><br>SECTION 1a (of 5): Initiating Memory.<br>SECTION 1b (of 5): Determining Offmap Flow.<br>
100%<br>SECTION 2: A * Search.<br>
100%<br>SECTION 3: Accumulating Surface Flow.<br> 100%<br>SECTION 4: Watershed determination.<br> 100%<br>SECTION 5: Closing Maps.<br> 100%<br><br></div> <span style="color: rgb(255, 0, 0);">Q: How do one really know the exact threshold value?</span><br style="color: rgb(255, 0, 0);">
<br>r.to.vect in=catch out=catchments feature=area<div class="im"><br>Extracting areas...<br> 100%<br> 100%<br>Building topology for vector map <catchments>...<br>Registering primitives...<br></div>134246 primitives registered<br>
701002 vertices registered<br>
Building areas...<br> 100%<br>44645 areas built<div class="im"><br>1 isles built<br>Attaching islands...<br> 100%<br>Attaching centroids...<br> 100%<br></div>Number of nodes: 89602<br>Number of primitives: 134246<div class="im">
<br>Number of points: 0<br>Number of lines: 0<br></div>
Number of boundaries: 89604<br>Number of centroids: 44642<br>Number of areas: 44645<br>Number of isles: 1<br>Number of areas without centroid: 3<br>r.to.vect complete.<br><br><br>g.region rast=rainfall<br><br>v.rast.stats vector=catchments raster=rainfall colprefix=precip<br>
WARNING: Area without centroid (may be OK for island)<br>WARNING: Area without centroid (may be OK for island)<br>WARNING: Area without centroid (may be OK for island)<div class="im"><br>DBMI-DBF driver error:<br>SQL parser error: syntax error, unexpected NULL_VALUE processing 'NULL'<br>
in statement:<br></div>UPDATE catchments SET precip_cf_=-NULL WHERE cat=17<div class="im"><br>Error in db_execute_immediate()<br><br></div>ERROR: Error while executing: 'UPDATE catchments SET precip_cf_=-NULL WHERE<br>
cat=17'<br><br><br>
- output of <a href="http://r.info" target="_blank">r.info</a> -g<br><br><a href="http://r.info" target="_blank">r.info</a> -g rainfall<br>north=40<br>south=-60<br>east=60<br>west=-20<br><br>- output of <a href="http://v.info" target="_blank">v.info</a><br>
<br><a href="http://v.info" target="_blank">v.info</a> -g catchments<br>
north=40<br>south=-60<br>east=60<br>west=-20<div class="im"><br>top=0.000000<br>bottom=0.000000<br><br></div>output of <a href="http://r.info" target="_blank">r.info</a><br><br>Type of Map: raster Number of Categories: 2559 <br>
Data Type: CELL <br>
Rows: 400 <br> Columns: 320 <br> Total Cells: 128000 <br>
Projection: Latitude-Longitude <br> N: 40N S: 60S Res: 0:15 <br> E: 60E W: 20W Res: 0:15 <br>
Range of data: min = 0 max = 2559 <br><div class="im"> <br> Data Description: <br>
generated by r.in.gdal <br> <br> Comments: <br>
</div>
r.in.gdal input="/home/tgumede1/grassdem/ict4eo/CapeTown_TRMMs.tif" \ <br> output="rainfall" target="CapeTown"<br><br><br>- output of r.univar<br><br>r.univar rainfall<br> 100%<br>
total null and non-null cells: 115200000<div class="im"><br>total null cells: 0<br><br>Of the non-null cells:<br>----------------------<br></div>n: 115200000<br>minimum: 0<br>maximum: 2559<br>range: 2559<br>mean: 22.4897<br>
mean of absolute values: 22.4897<br>
standard deviation: 83.1312<br>variance: 6910.79<br>variation coefficient: 369.642 %<br>sum: 2590809300<div><div></div><div class="h5"><br><br><br><br><br><br>-- <br>Kind Regards<br>TS Gumede<br>CSIR, Meraka Institute<br>
072 258 1650<br><br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>Kind Regards<br>TS Gumede<br>CSIR, Meraka Institute<br>072 258 1650<br><br>