<div dir="ltr"><div><div><div>Thanks all for the responses. After few days of struggle and yes most of you are correct. I found easy solution to the problem for using the Mercator projection. wrf2grads uses constant increment in y. But the
latitudes in the nc output are not equidistant. When we replaced the
constant increment by the latitudes specified by the nc file the problem
seems to disapear.<br><br>To incorporate this correction to the original program we replace the line in the subroutine create_grads in the file module_wrf_to_grads_util.F. <dl class=""><dt><a href="http://forum.wrfforum.com/viewtopic.php?f=30&t=517#"></a></dt>
<dd>By replacing the below section <br></dd><dd><code></code></dd><dd><code> write(13,'("ydef ",i4," levels ")')ny &<br> ny,xlat(1,1),(abs(xlat(1,1)-xlat(nx,ny))/(ny-1))</code></dd>
</dl>with<dl class=""><dd><code> write(13,'("ydef ",i4," levels ")')ny<br> do my_var = 1 , ny<br> write(13,'(" ",f10.5)')xlat(1,my_var)<br> enddo</code></dd>
</dl>and recompile wrf2grads. <br><br></div>This will just list out all the latitudes. instead of setting linear YDEF with constant increment. I am not sure why Mercator projection is still not supported by grads. But this could be a better work-around. This worked extremely well for me. <br>
<br></div>regards,<br></div>Itesh<br><div><div><div><div><br><br></div></div></div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Jul 12, 2013 at 8:42 PM, Masters.Steve <span dir="ltr"><<a href="mailto:masters.steve@ensco.com" target="_blank">masters.steve@ensco.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div link="blue" vlink="purple" lang="EN-US">
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I have plotted WRF data in grib format with a Mercator projection and it appears to plot correctly. The <a href="http://grib2ctl.pl" target="_blank">grib2ctl.pl</a> script that builds the ctl file constructs
the YDEF line like<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">YDEF 120 LEVELS -3.325 -3.305 -3.287 ….. <120 levels given><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">It calculates and puts in the actual latitudes of the grid points for the particular Mercator grid that is defined in the file. The levels in the YDEF (or
XDEF) do not need to be at even intervals so this method appears to work for the Mercator-projection data. <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">For your application, you can pull out the latitudes of the grid points from one of the wrfout* files using something like “ncdump –v CLAT wrfout…” and build
the YDEF line from these values.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Steve Masters
<a href="mailto:masters.steve@ensco.com" target="_blank">masters.steve@ensco.com</a><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">ENSCO, Inc.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Melbourne, FL<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <a href="mailto:gradsusr-bounces@gradsusr.org" target="_blank">gradsusr-bounces@gradsusr.org</a> [mailto:<a href="mailto:gradsusr-bounces@gradsusr.org" target="_blank">gradsusr-bounces@gradsusr.org</a>]
<b>On Behalf Of </b>Yaqiang Wang<br>
<b>Sent:</b> Friday, July 12, 2013 1:23 AM<br>
<b>To:</b> GrADS Users Forum<br>
<b>Subject:</b> Re: [gradsusr] Shift in the lattitude while plotting in grads mercator/latlon projction<u></u><u></u></span></p><div><div class="h5">
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Mercator projection is longitude equal-interval but not latitude equal-interval. The ctl without PDEF (Mercator is not supported in PDEF at present) may approximatively plot the data at low latitude area, but it's imposible plot the data
at exactly position.<br>
<br>
On Friday, July 12, 2013, itesh dash wrote:<u></u><u></u></p>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in">
<div>
<p class="MsoNormal">The information actually were extracted from in the namelist.wps file using WRF2GrAGS which generate the control(ctl) file. For the model I only provided the grid resolution(9km), no of grid points in both north south (640) and east west(460)
and center latitude and longitude (18.0 and 91.0). <u></u><u></u></p>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">The XDEF,YDEF and other params were automatically calculated by WRF2Grads. But your guessing may be correct as i have changed the start lat from -3.1006 to -2.1006 and the shift is minimized. BUt is this correct way?<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">I am currently using the mercator projection. I will change to lat-lon projection and see if that makes the difference. <u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">Thanks.<u></u><u></u></p>
<div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
</div>
</div>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p>
<div>
<p class="MsoNormal">On Fri, Jul 12, 2013 at 12:40 AM, James T. Potemra <<a href="mailto:jimp@hawaii.edu" target="_blank">jimp@hawaii.edu</a>> wrote:<u></u><u></u></p>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in">
<div>
<p class="MsoNormal">Itesh:<br>
<br>
Your model output is 640 x 460, but your descriptor file has<br>
xdef = 639 and ydef = 459. These should be 640 and 460,<br>
respectively. Also, I think what Mohsen meant was to make<br>
sure your starting lat/lon is the same in the descriptor file<br>
and model grid, i.e., you have 61.1815 as the starting lon<br>
and -3.1006 as the starting lat. Are these the same as the<br>
model grid?<br>
<br>
Jim<u></u><u></u></p>
<div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p>
<div>
<p class="MsoNormal">On 7/11/13 7:31 AM, itesh dash wrote:<u></u><u></u></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal">Dear Mohsen, <u></u><u></u></p>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">thanks for the response. But I am not even trying to use any script. Just by opening and plotting the ctl file.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">Here is my ctl file<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<div>
<p class="MsoNormal">dset ^Jul1013_12.dat<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">undef 1.e35<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">xdef 639 linear 61.1815 0.0935<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">ydef 459 linear -3.1006 0.0873<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">zdef 3 levels<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> 850.00000<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> 500.00000<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"> 200.00000<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">tdef 8 linear 12z10jul2013 6hr<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">vars 1<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">HGT 0 0 Terrain Height<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">endvars<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">The wrf model ran with mercator projection 640 x 460 grid points 9 km resolution.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">I could not figure out why the shift is there. Is there a way i can balance the shift.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">regards,<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">itesh<u></u><u></u></p>
</div>
</div>
</div>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p>
<div>
<p class="MsoNormal">On Thu, Jul 11, 2013 at 11:58 PM, Mohsen Soltani <<a href="mailto:soltani.clima@gmail.com" target="_blank">soltani.clima@gmail.com</a>> wrote:<u></u><u></u></p>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in">
<div>
<div>
<p class="MsoNormal"><span style="font-family:"Tahoma","sans-serif";color:#0b5394">itesh,<u></u><u></u></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Tahoma","sans-serif";color:#0b5394"><u></u> <u></u></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Tahoma","sans-serif";color:#0b5394">Make sure Lat/Lon in your .ctl file are the same as your script!<u></u><u></u></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Tahoma","sans-serif";color:#0b5394"><u></u> <u></u></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Tahoma","sans-serif";color:#0b5394">Mohsen<u></u><u></u></span></p>
</div>
</div>
<div>
<p class="MsoNormal"><br clear="all">
<u></u><u></u></p>
<div>
<div>
<p class="MsoNormal">-- <u></u><u></u></p>
<div>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#274e13">April showers bring May flowers!</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">--<span style="color:#b45f06"> <br>
<b>Mohsen Soltani, M.Sc.</b><br>
Climatology Grad Student,<br>
Department of Climatology, Faculty of Geography,</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#b45f06">University of Tehran, Tehran, Iran</span><u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><span style="color:#b45f06">voice: (+98) 9119772934<br>
e-mail</span><span style="color:#bf9000">:</span> <a href="mailto:soltani.clima@gmail.com" target="_blank">
soltani.clima@gmail.com</a><u></u><u></u></p>
</div>
</div>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p>
<div>
<div>
<div>
<p class="MsoNormal">On Thu, Jul 11, 2013 at 9:05 AM, itesh dash <<a href="mailto:itesh@rimes.int" target="_blank">itesh@rimes.int</a>> wrote<u></u><u></u></p>
</div>
</div>
</div>
</div>
</blockquote>
</div>
</div>
</blockquote>
</div>
</div>
</div>
</blockquote>
</div>
</div>
</blockquote>
<p class="MsoNormal"><br>
<br>
-- <br>
*************************************************<br>
Dr. Yaqiang Wang<br>
Chinese Academy of Meteorological Sciences (CAMS)<br>
46, Zhong-Guan-Cun South Avenue<br>
Beijing, 100081<br>
China<br>
<span style="font-family:"Calibri","sans-serif""> </span><br>
<a href="mailto:yaqiang.wang@gmail.com" target="_blank">yaqiang.wang@gmail.com</a><br>
<br>
<a href="http://www.meteothinker.com" target="_blank">http://www.meteothinker.com</a><br>
**************************************************<u></u><u></u></p>
</div></div></div>
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