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Dear Dr. Dan,<br>
<br>
I have not changed the units to inch it is the same "kg per sqr meter".
The problem is with 'undef' in the ctl file. As per the data
distributer documentation undef is the highest value (counts) i.e.
65535 (=2^16 -1). But, if you will see the data through 'set gxout
stat' the max. value is 55537. Again the counts need to be scaled with
0.1. As per the instructions in the header file the max valid data
value is 581 kg per sqr meter (=counts x 0.1).<br>
<br>
Please see the ctl whether it is "unpack 1.0 0.0" or "unpack 0.1 0.0".
If it is the second one no need to multiply the counts (snow) with 0.1.
And if you write the "undef 55537" you will not get shading outside the
valied data areas. Earlier I had used undef as 65535 (as per their
docs) and I had maskout values > 581. See the attached ctl and gs
scripts used to produced the image ' snow.jpeg' (sending you in a
separate e-mail off the list due to bigger size).<br>
<pre class="moz-signature" cols="72">
Thanking you.
With Best Regards,
M. Mahakur
----------------------------------------------------------
M. Mahakur
FORECASTING RESEARCH DIVISION
INDIAN INSTITUTE OF TROPICAL METEOROLOGY
(Min. of Earth Sciences, Govt. of India)
DR. HOMI BHABHA ROAD
NCL POST, PASHAN
PUNE - 411 008
INDIA.
-----------------------------------------------------------</pre>
<br>
Dan Leins wrote:
<blockquote
cite="mid46e821750707260921u198637cdxaae161b0cd218649@mail.gmail.com"
type="cite">
<div>Mahakur,</div>
<div> </div>
<div>Thank you for your help. I do have a question for you though. </div>
<div> </div>
<div>I downloaded the same file and tried to display the same data
using the provided control file. However my image looks nothing like
yours. Did you just open the control file and </div>
<div> </div>
<div>'d snow' ?</div>
<div> </div>
<div>Or did you multiply it by 0.039etc...... to convert it to
inches? Even when I do that, I get an image with a small contour over
the central part of the US, but nothing representative. What commands
did you use when you opened the control file?
</div>
<div> </div>
<div>Thanks,</div>
<div>Dan<br>
</div>
<div><span class="gmail_quote">On 7/24/07, <b
class="gmail_sendername">M.Mahakur</b> <<a
href="mailto:mmahakur@tropmet.res.in">mmahakur@tropmet.res.in</a>>
wrote:</span>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0px 0px 0px 0.8ex; padding-left: 1ex;">
<div text="#000000" bgcolor="#ffffff">Dear Dr. Dan,<br>
<br>
I tried to pull the following small tarball and since it is a ONLY ONE
band BIL I feel it could be display using GrADS.<br>
<br>
<a onclick="return top.js.OpenExtLink(window,event,this)"
href="ftp://sidads.colorado.edu/DATASETS/NOAA/G02158/SNODAS_20070722.tar"
target="_blank">ftp://sidads.colorado.edu/DATASETS/NOAA/G02158/SNODAS_20070722.tar</a><br>
<br>
Looking at the Header I tried. Please see the attached ctl and image
file. It is a 16 bit raster image but I feel the valid data is max 581
(within 10 bits) kg per sqr m. I did not understand what is meant ny
axis offset, so just ignored!
<br>
<br>
Regards,<br>
<span class="sg"><br>
Mahakur</span>
<div><span class="e" id="q_113f7e1ea49b56d9_2"><br>
<br>
Dan Leins wrote:
<blockquote
cite="http://mid46e821750707230948m21b63834n825ac0e8fd649397@mail.gmail.com"
type="cite">
<div>All,</div>
<div> </div>
<div>I am trying to download and view a gridded dataset of 24hr
snowfall from NOAA/NOHRSC using GrADS. So far, I've downloaded the
dataset in question, un-tarred it and briefly read through some
information about the data type. It would appear to contain 2 files,
one a text header and the other a binary raster file. Does anyone know
if GrADS will accept this as a data type, and if not, how to convert it
to something a little more "GrADS-friendly"? I've worked with binary
files in the past so I'm aware that GrADS can use binary files so long
as there is a control file specified, however I wouldn't even know
where to begin looking for or creating a control file from scratch.
</div>
<div> </div>
<div>The data in question can be accessed here...</div>
<div><a onclick="return top.js.OpenExtLink(window,event,this)"
href="http://www.nohrsc.noaa.gov/archived_data/instructions.html"
target="_blank">http://www.nohrsc.noaa.gov/archived_data/instructions.html</a></div>
<div> </div>
<div>Thanks,</div>
<div>Dan</div>
</blockquote>
<br>
<br>
</span></div>
</div>
<br>
dset us_ssmv01025SlL00T0024TTNATS2007072205DP001.dat<br>
title test<br>
UNPACK 1.0 0.0<br>
options yrev<br>
#undef -9999.0<br>
undef 65535<br>
xdef 6935 linear -124.729583333333 0.00833333333333333<br>
ydef 3351 linear 24.9495833333324 0.00833333333333333<br>
zdef 1 levels 1000<br>
tdef 1 linear 22jul2007 1dy<br>
vars 1<br>
snow 0 -1,40,2 (0.1 kilometer per square meter)<br>
endvars<br>
<br>
<br>
<br clear="all">
</blockquote>
</div>
<br>
</blockquote>
<br>
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