[GRASS-user] v.rast.stats

[Sandile Gumede]

Hi

It is still giving me -NULL value error.

Do you think maybe its the way I downloaded my rainfall data? This is the
site where I downloaded my data sets* ftp://trmmopen.gsfc.nasa.gov/pub/gis/
*and this data covers the whole world, the only thing I did was to clip a
specific region (using coordinates) that is in South Africa to do my
analysis. I used a bash script to download and project the data, see below:


#!/bin/bash

wget ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif
wget ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw

gdal_translate -of GTiff -co "PROFILE=GeoTIFF" -co "INTERLEAVE=PIXEL" -co
"COMPRESS=LZW" -co "TILED=YES" -a_srs EPSG:4326 -a_ullr 18.2987501
-33.6795831 19.1712501 -34.3487498 3B42RT.2010032900.1day.tif
TRMMLast1day.tif



2010/6/15 Micha Silver <micha at arava.co.il>

>  On 15/06/2010 14:35, Sandile Gumede wrote:
>
> Hi
> If I run g.region rast=rainfall -p, I get:
>
> OK, what you've done here is change the current region to match the raster
> "rainfall".
> Can you now try:
> v.rast.stats -c vect=catchments rast=rainfall pref=precip
>
>
>
>
> projection: 3 (Latitude-Longitude)
> zone:       0
> datum:      wgs84
> ellipsoid:  wgs84
> north:      33:40:46.49916S
> south:      34:20:55.49928S
> west:       18:17:55.50036E
> east:       19:10:16.50036E
> nsres:      0:00:05.01875
> ewres:      0:00:02.18125
> rows:       480
> cols:       1440
> cells:      691200
>
> and If I run r.univar rainfall, I get the following output:
>
>  100%
> total null and non-null cells: 691200
> total null cells: 0
>
> Of the non-null cells:
> ----------------------
> n: 691200
> minimum: 0
> maximum: 3094
> range: 3094
> mean: 22.0228
> mean of absolute values: 22.0228
> standard deviation: 76.1639
> variance: 5800.94
> variation coefficient: 345.841 %
> sum: 15222164
>
>
>
> On Tue, Jun 15, 2010 at 12:22 PM, Hamish <hamish_b at yahoo.com> wrote:
>
>> Micha wrote:
>> > The only unusual thing I notice above is that the resolution settings
>> > for the raster are different N-S and E-W. This came from the original
>> > tiff (see below) which also has rectangular pixels,
>>
>>  that is perfectly normal for a lat/lon map away from the equator.
>> longitude scales a cos(lat).
>>
>>
>> > (the v.rast.stats module creates a temp raster at the *current region's
>> > resolution* settings, which might be different from this rainfall
>> > raster's rectangular resolution...)
>>
>>  the results of:
>>
>> g.region -p rast=mapname
>> r.univar mapname
>>
>>
>> could help.
>>
>>
>> Hamish
>>
>>
>>
>>
>
>
> --
> Kind Regards
> TS Gumede
> CSIR, Meraka Institute
> 072 258 1650
>
>
> This mail was received via Mail-SeCure System.
>
>
>
> --
> Micha Silverhttp://www.surfaces.co.il/
> Arava Development Co.  +972-52-3665918
>
>


-- 
Kind Regards
TS Gumede
CSIR, Meraka Institute
072 258 1650
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