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<DIV><FONT face=Arial size=2>Jim,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Excellent! That is more than enough
to get me started. Thanks very much for the detailed explanation and
sample - very helpful for a GrADS/OpenDAP rookie like myself!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Mark</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=jimp@HAWAII.EDU href="mailto:jimp@HAWAII.EDU">James T. Potemra</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=GRADSUSR@LIST.CINECA.IT
href="mailto:GRADSUSR@LIST.CINECA.IT">GRADSUSR@LIST.CINECA.IT</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, November 12, 2009 11:05
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: OpenDAP GRIB Retrieval from
Nomads</DIV>
<DIV><BR></DIV>Hi Mark:<BR><BR>Should be pretty straightforward. Just
follow the link you give below<BR>and you should see a list of the GDS catalog
at nomads (the listing has<BR>names like gfs20091101). Select whichever
date in which you are<BR>interested, and you should see a page with the data
set catalog. For<BR>example, I just clicked on the top one gfs20091014
and got a list with<BR>gfs_00z, gfs_00z_anl, etc. Again, pick the one of
interest and click on<BR>the "info" link. E.g., I clicked on the "info"
link next to gfs_00z<BR>(the direct URL is<BR><A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z.info">http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z.info</A>).<BR>All
you need is the "OPeNDAP/DODS Data URL" listed at the top, again in<BR>this
case it is<BR><A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z</A><BR>(Note
here that you can't always assume the syntax of the DODS Data URL<BR>will be
similar to the catalog URL, but in this case it happens to be).<BR>So, now all
you need to do is fire up GrADS (or gradsdods depending on<BR>your binary
version), then type in "sdfopen xxx" where "xxx" is the DODS<BR>data URL from
above. You should then have total access to the data set,<BR>at which
point you'll first be amazed at the simplicity with which you<BR>can access
data without actually having to transfer/reformat/etc., and<BR>then you'll be
looking for a way to thank all the brilliant minds that<BR>provide us with
this capability. The final step, if you really want to<BR>download, is
just "set lat ...", "set lon...", "set lev...", "set<BR>time..", "set gxout
fwrite" and "d variable".<BR><BR>Jim<BR><BR>PS. Here's what it looks
like for the sample file:<BR><BR>grads
-l<BR><BR>
Welcome to the OpenGrADS Bundle
Distribution<BR>
--------------------------------------------<BR><BR>For additional information
enter "grads
-h".<BR><BR>Starting<BR>"/usr/local/grads-2.0.a7.oga.2/Contents/Linux/Versions/2.0.a7.oga.2/x86_64/grads<BR>-l
" ...<BR><BR><BR>Grid Analysis and Display System (GrADS) Version
2.0.a7.oga.2<BR>Copyright (c) 1988-2008 by Brian Doty and the<BR>Institute for
Global Environment and Society (IGES)<BR>GrADS comes with ABSOLUTELY NO
WARRANTY<BR>See file COPYRIGHT for more information<BR><BR>Config:
v2.0.a7.oga.2 little-endian readline printim grib2 netcdf<BR>hdf4-sds hdf5
opendap-grids,stn athena geotiff<BR>Issue 'q config' command for more
information.<BR>Loading User Defined Extensions
table<BR></usr/local/grads-2.0.a7.oga.2/Contents/Linux/Versions/2.0.a7.oga.2/x86_64/gex/udxt><BR>...
ok.<BR>GX Package Initialization: Size = 11 8.5<BR>ga-> sdfopen <A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z</A><BR>Scanning
self-describing file:<BR><A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z</A><BR>SDF
file <A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z</A><BR>is
open as file 1<BR>LON set to 0 360<BR>LAT set to -90 90<BR>LEV set to 1000
1000<BR>Time values set: 2009:10:14:0 2009:10:14:0<BR>E set to 1 1<BR>ga->
q file<BR>File 1 : GFS fcst starting from 00Z14oct2009, downloaded Oct 14
04:24 UTC<BR> Descriptor: <A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z</A><BR>
Binary: <A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z">http://nomads.ncep.noaa.gov:9090/dods/gfs/gfs20091014/gfs_00z</A><BR>
Type = Gridded<BR> Xsize = 360 Ysize = 181 Zsize = 26
Tsize = 61 Esize = 1<BR> Number of Variables =
139<BR> absvprs 26 t,z,y,x ** (1000
975 950 925 900.. 70 50 30 20 10)<BR>none absolute vorticity
[1/s]<BR> no4lftxsfc 0 t,y,x **
surface none best (4 layer) lifted index [k]<BR>
no5wava500mb 0 t,y,x ** 500 mb none 5-wave geopotential
height<BR>anomaly [gpm]<BR> no5wavh500mb 0
t,y,x ** 500 mb none 5-wave geopotential
height<BR>[gpm]<BR>....<BR><BR>ga-> set lat -90 90<BR>LAT set to -90
90<BR>ga-> set lon 130 150<BR>LON set to 130 150<BR>ga-> set t 1<BR>Time
values set: 2009:10:14:0 2009:10:14:0<BR>ga-> set z 1<BR>LEV set to 1000
1000<BR>ga-> set gxout fwrite<BR>ga-> d ugrdprs<BR>Wrote 3801 of 3801
elements to grads.fwrite as Stream Little_Endian<BR><BR><BR><BR>Mark Hess
wrote:<BR>> All,<BR>><BR>> I tried to search the GRADSUSR archives
for the answer to this<BR>> question, but it gives me the error errno=146
"unable to initiate<BR>> communication...". Perhaps you all can offer
an answer.<BR>><BR>> Does anyone have any sample strings for use with
gradsdods to retreive<BR>> a GFS grib file from the NWS NCEP MOMANDS
OpenDAP server?<BR>> (<A
href="http://nomads.ncep.noaa.gov:9090/dods/gfs">http://nomads.ncep.noaa.gov:9090/dods/gfs</A>)<BR>><BR>>
I'm especially interested in how to extract data for a specified<BR>>
geographical region.<BR>><BR>> If anyone can get me started with this, I
should be able to take an<BR>> example and work from there.<BR>><BR>>
Thank you.<BR>><BR>> Mark<BR>></BLOCKQUOTE></BODY></HTML>