<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html style="direction: rtl;">
<head>
<meta content="text/html; charset=windows-1255"
http-equiv="Content-Type">
</head>
<body style="direction: ltr;" bgcolor="#ffffff" text="#000000">
On 15/07/2010 09:57, Sandile Gumede wrote:
<blockquote style="direction: ltr;"
cite="mid:AANLkTilK_bXJfOuKlb6XIX9Q-ED3iEEySdojYERkCOAF@mail.gmail.com"
type="cite">Hi Micha<br>
<br>
Which DEM data you used to test this rainfall data?<br>
<br>
Can I have it?<br>
</blockquote>
I did the exercise below based on the ASTER DEM data from the US JPL
program.<br>
You can download data for anywhere in the world, at 30 m. resolution,
from:<br>
<a class="moz-txt-link-freetext" href="https://wist.echo.nasa.gov/~wist/api/imswelcome/">https://wist.echo.nasa.gov/~wist/api/imswelcome/</a><br>
It requires registering, then after you manage to login, type ASTER DEM
in the keyword search. Next scroll down to the Search Area section, and
select one of the methods to mark the region you want. Eventually
you'll be able to finish the query and they send you an email that the
search has completed, with a download link to get the data.<br>
<br>
<blockquote style="direction: ltr;"
cite="mid:AANLkTilK_bXJfOuKlb6XIX9Q-ED3iEEySdojYERkCOAF@mail.gmail.com"
type="cite"><br>
<div style="direction: ltr;" class="gmail_quote">On Sat, Jun 19, 2010
at 9:57 PM, Micha Silver <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:micha@arava.co.il">micha@arava.co.il</a>></span> wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; direction: ltr;">
<div style="direction: ltr;" bgcolor="#ffffff" text="#000000">
Hello Sandile:<br>
I tried to duplicate your steps and it seems to work for me.<br>
Here's what I did:
<div style="direction: ltr;" class="im"><br>
<br>
wget <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif"
target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif</a><br>
wget <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw"
target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw</a><br>
<br>
</div>
gdalinfo 3B42RT.2010032900.1day.tif<br>
Driver: GTiff/GeoTIFF<br>
Files: 3B42RT.2010032900.1day.tif<br>
3B42RT.2010032900.1day.tfw<br>
Size is 1440, 480<br>
Coordinate System is `'<br>
Origin = (-180.000000000000000,60.000000000000000)<br>
Pixel Size = (0.250000000000000,-0.250000000000000)<br>
....<br>
<br>
---- Note: no projection info above ----<br>
<br>
---- Now I use the -projwin option of gdal_translate to select a small
window <br>
gdal_translate -a_srs EPSG:4326 -projwin 34.0 33.0 36.0 29.0
3B42RT.2010032900.1day.tif rainfall_il.tif<br>
<br>
---- GEOGCS entry now shows 4326 ----<br>
<br>
g.mapset map=ASTER_DEM loc=WGS84 <br>
----- A location setup as EPSG:4326----<br>
<br>
r.in.gdal israel.tif out=rainfall_il<br>
<br>
r.univar rainfall_il<br>
100%<br>
total null and non-null cells: 77760000
<div style="direction: ltr;" class="im"><br>
total null cells: 0<br>
<br>
Of the non-null cells:<br>
----------------------<br>
</div>
n: 77760000<br>
minimum: 0<br>
maximum: 34<br>
range: 34<br>
mean: 0.364583<br>
mean of absolute values: 0.364583<br>
standard deviation: 3.45241<br>
variance: 11.9192<br>
variation coefficient: 946.948 %<br>
sum: 28350000<br>
<br>
<br>
----- Now using an existing catchment vector map ----<br>
v.rast.stats vect=arava_wsheds rast=rainfall_il colpre=precip<br>
<a moz-do-not-send="true" href="http://v.info" target="_blank">v.info</a>
-c arava_wsheds<br>
Displaying column types/names for database connection of layer 1:<br>
INTEGER|cat<br>
CHARACTER|label<br>
DOUBLE PRECISION|area_km<br>
INTEGER|precip_n<br>
DOUBLE PRECISION|precip_min<br>
DOUBLE PRECISION|precip_max<br>
DOUBLE PRECISION|precip_range<br>
DOUBLE PRECISION|precip_mean<br>
DOUBLE PRECISION|precip_stddev<br>
DOUBLE PRECISION|precip_variance<br>
DOUBLE PRECISION|precip_cf_var<br>
DOUBLE PRECISION|precip_sum<br>
<br>
---- and some values ----<br>
<br>
v.db.select arava_wsheds <br>
cat|label|area_km|precip_n|precip_min|precip_max|precip_range|precip_mean|precip_stddev|precip_variance|precip_cf_var|precip_sum<br>
21|Jordan|1055.231692|2|0|0|0|0|0|0||0<br>
19|Hidan|987.811979|2|0|0|0|0|0|0||0<br>
28|Og|124.122969|||||||||<br>
36|Zarqa|273.606213|||||||||<br>
24|Kidron|122.460114|||||||||<br>
9|Darga|289.012122|||||||||<br>
6|Arugot|236.365116|1|0|0|0|0|0|0||0<br>
26|Mujib|1277.546513|2|0|0|0|0|0|0||0<br>
<br>
---- (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.)----<br>
<br>
HTH...<br>
-- <br>
Micha
<div style="direction: ltr;">
<div style="direction: ltr;" class="h5"><br>
<br>
<br>
On 06/17/2010 12:50 PM, Sandile Gumede wrote:
<blockquote style="direction: ltr;" type="cite">Hi<br>
<br>
It is still giving me -NULL value error.<br>
<br>
Do you think maybe its the way I downloaded my rainfall data? This is
the site where I downloaded my data sets<u> <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/" target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/</a>
</u>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:<br>
<br>
<br>
#!/bin/bash<br>
<br>
wget <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif"
target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif</a><br>
wget <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw"
target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw</a><br>
<br>
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<br>
<br>
<br>
<br>
<br>
<div style="direction: ltr;" class="gmail_quote">On Thu, Jun 17,
2010 at 8:41 AM, Sandile
Gumede <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:akasandile@gmail.com" target="_blank">akasandile@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; direction: ltr;">Hi<br>
<br>
It is still giving me -NULL value error.<br>
<br>
Do you think maybe its the way I downloaded my rainfall data? This is
the site where I downloaded my data sets<u> <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/" target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/</a>
</u>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:<br>
<br>
<br>
#!/bin/bash<br>
<br>
wget <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif"
target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tif</a><br>
wget <a moz-do-not-send="true"
href="ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw"
target="_blank">ftp://trmmopen.gsfc.nasa.gov/pub/gis/3B42RT.2010032900.1day.tfw</a><br>
<br>
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<br>
<br>
<br>
<br>
<div style="direction: ltr;" class="gmail_quote">
<div style="direction: ltr;">2010/6/15 Micha Silver <span
dir="ltr"><<a moz-do-not-send="true" href="mailto:micha@arava.co.il"
target="_blank">micha@arava.co.il</a>></span><br>
</div>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; direction: ltr;">
<div style="direction: ltr;" bgcolor="#ffffff" text="#000000">
<div style="direction: ltr;">On 15/06/2010 14:35, Sandile
Gumede wrote:
<div style="direction: ltr;">
<div style="direction: ltr;">
<blockquote style="direction: ltr;" type="cite">Hi<br>
If I run g.region rast=rainfall -p, I get:<br>
</blockquote>
</div>
</div>
</div>
<div style="direction: ltr;">
<div style="direction: ltr;">OK, what you've done here is
change the current
region to match the
raster "rainfall".<br>
Can you now try: <br>
v.rast.stats -c vect=catchments rast=rainfall pref=precip<br>
<br>
<br>
<blockquote style="direction: ltr;" type="cite">
<div style="direction: ltr;">
<div style="direction: ltr;"><br>
projection: 3 (Latitude-Longitude)<br>
zone: 0<br>
datum: wgs84<br>
ellipsoid: wgs84<br>
north: 33:40:46.49916S<br>
south: 34:20:55.49928S<br>
west: 18:17:55.50036E<br>
east: 19:10:16.50036E<br>
nsres: 0:00:05.01875<br>
ewres: 0:00:02.18125<br>
rows: 480<br>
cols: 1440<br>
cells: 691200<br>
<br>
and If I run r.univar rainfall, I get the following output:<br>
<br>
100%<br>
total null and non-null cells: 691200<br>
total null cells: 0<br>
<br>
Of the non-null cells:<br>
----------------------<br>
n: 691200<br>
minimum: 0<br>
maximum: 3094<br>
range: 3094<br>
mean: 22.0228<br>
mean of absolute values: 22.0228<br>
standard deviation: 76.1639<br>
variance: 5800.94<br>
variation coefficient: 345.841 %<br>
sum: 15222164<br>
<br>
<br>
<br>
<div style="direction: ltr;" class="gmail_quote">On Tue,
Jun 15, 2010 at 12:22 PM,
Hamish <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:hamish_b@yahoo.com" target="_blank">hamish_b@yahoo.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; direction: ltr;">
<div style="direction: ltr;">Micha wrote:<br>
> The only unusual thing I notice above is that the resolution
settings<br>
> for the raster are different N-S and E-W. This came from the
original<br>
> tiff (see below) which also has rectangular pixels,<br>
<br>
</div>
that is perfectly normal for a lat/lon map away from the equator.<br>
longitude scales a cos(lat).<br>
<div style="direction: ltr;"><br>
<br>
> (the v.rast.stats module creates a temp raster at the *current
region's<br>
> resolution* settings, which might be different from this rainfall<br>
> raster's rectangular resolution...)<br>
<br>
</div>
the results of:<br>
<br>
g.region -p rast=mapname<br>
r.univar mapname<br>
<br>
<br>
could help.<br>
<font color="#888888"><br>
<br>
Hamish<br>
<br>
<br>
<br>
</font></blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Kind Regards<br>
TS Gumede<br>
CSIR, Meraka Institute<br>
072 258 1650<br>
<br>
<br>
</div>
</div>
<div style="direction: ltr;">This mail was received via
Mail-SeCure System.<br>
</div>
</blockquote>
<div style="direction: ltr;"><br>
<br>
<pre style="direction: ltr;" cols="62">--
Micha Silver
<a moz-do-not-send="true" href="http://www.surfaces.co.il/"
target="_blank">http://www.surfaces.co.il/</a>
Arava Development Co. +972-52-3665918
</pre>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<div style="direction: ltr;">
<div style="direction: ltr;"><br>
<br clear="all">
<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>
<br>
This mail was received via Mail-SeCure System.<br>
</blockquote>
<br>
<br>
</div>
</div>
<pre style="direction: ltr;" cols="72">--
Micha Silver
Arava Development Co. +972-52-3665918
<a moz-do-not-send="true" href="http://surfaces.co.il" target="_blank">http://surfaces.co.il</a>
</pre>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Kind Regards<br>
TS Gumede<br>
CSIR, Meraka Institute<br>
072 258 1650<br>
<br>
<br>
This mail was received via Mail-SeCure System.<br>
</blockquote>
<br>
<br>
<pre style="direction: ltr;" class="moz-signature" cols="62">--
Micha Silver
<a class="moz-txt-link-freetext" href="http://www.surfaces.co.il/">http://www.surfaces.co.il/</a>
Arava Development Co. +972-52-3665918
</pre>
</body>
</html>