Hello Sandile:
I tried to duplicate your steps and it seems to work for me.
Here's what I did:
wget ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif
wget ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw
gdalinfo 3B42RT.2010032900.1day.tif
Driver: GTiff/GeoTIFF
Files: 3B42RT.2010032900.1day.tif
3B42RT.2010032900.1day.tfw
Size is 1440, 480
Coordinate System is `'
Origin = (-180.000000000000000,60.000000000000000)
Pixel Size = (0.250000000000000,-0.250000000000000)
....
---- Note: no projection info above ----
---- Now I use the -projwin option of gdal_translate to select a small
window
gdal_translate -a_srs EPSG:4326 -projwin 34.0 33.0 36.0 29.0
3B42RT.2010032900.1day.tif rainfall_il.tif
---- GEOGCS entry now shows 4326 ----
g.mapset map=ASTER_DEM loc=WGS84
----- A location setup as EPSG:4326----
r.in.gdal israel.tif out=rainfall_il
r.univar rainfall_il
100%
total null and non-null cells: 77760000
total null cells: 0
Of the non-null cells:
----------------------
n: 77760000
minimum: 0
maximum: 34
range: 34
mean: 0.364583
mean of absolute values: 0.364583
standard deviation: 3.45241
variance: 11.9192
variation coefficient: 946.948 %
sum: 28350000
----- Now using an existing catchment vector map ----
v.rast.stats vect=arava_wsheds rast=rainfall_il colpre=precip
v.info -c arava_wsheds
Displaying column types/names for database connection of layer 1:
INTEGER|cat
CHARACTER|label
DOUBLE PRECISION|area_km
INTEGER|precip_n
DOUBLE PRECISION|precip_min
DOUBLE PRECISION|precip_max
DOUBLE PRECISION|precip_range
DOUBLE PRECISION|precip_mean
DOUBLE PRECISION|precip_stddev
DOUBLE PRECISION|precip_variance
DOUBLE PRECISION|precip_cf_var
DOUBLE PRECISION|precip_sum
---- and some values ----
v.db.select arava_wsheds
cat|label|area_km|precip_n|precip_min|precip_max|precip_range|precip_mean|precip_stddev|precip_variance|precip_cf_var|precip_sum
21|Jordan|1055.231692|2|0|0|0|0|0|0||0
19|Hidan|987.811979|2|0|0|0|0|0|0||0
28|Og|124.122969|||||||||
36|Zarqa|273.606213|||||||||
24|Kidron|122.460114|||||||||
9|Darga|289.012122|||||||||
6|Arugot|236.365116|1|0|0|0|0|0|0||0
26|Mujib|1277.546513|2|0|0|0|0|0|0||0
---- (Many catchments have 0 or no value because of the small region I
chose. The global data is 1/4 degree resolution and my region is only 2
deg E-W.)----
HTH...
--
Micha
On 06/17/2010 12:50 PM, Sandile Gumede wrote:
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
On Thu, Jun 17, 2010 at 8:41 AM, Sandile Gumede <[email protected]
<mailto:[email protected]>> wrote:
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 <[email protected] <mailto:[email protected]>>
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 <[email protected]
<mailto:[email protected]>> 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 Silver
http://www.surfaces.co.il/
Arava Development Co. +972-52-3665918
--
Kind Regards
TS Gumede
CSIR, Meraka Institute
072 258 1650
--
Kind Regards
TS Gumede
CSIR, Meraka Institute
072 258 1650
This mail was received via Mail-SeCure System.
--
Micha Silver
Arava Development Co. +972-52-3665918
http://surfaces.co.il
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