[gradsusr] NCEP global SST data and GrADS

[Jennifer M Adams]

Hi, Bill — 
The problem is that GrADS has determined that your grid does not wrap the globe. The error is in your XDEF declaration. You have 
    XDEF 4321 LINEAR -179.958333 0.083333
which you say you got from degrib. That is incorrect. The size should be 4320 — the grid as you’ve defined it actually overlaps and therefore fails the globe-wrapping test in GrADS (if longitude at x=1 is roughly the same as longitude at x=xsize+1)

Since your descriptor file is for a flat binary file and not a grib2 file, I suspect you may have stuck an extra column of data onto your grid when converting the format. 

I downloaded the grib2 file in question and used g2ctl to get a descriptor and got this for XDEF:
   XDEF 4320 linear 0.042000 0.083000

Your grid size is clearly 4320 and not 4321. A quick check of the initial lon value confirms that the grib2 grid goes from 0 to 360 and not -180 to 180. 

Here is my complete descriptor: 
dset ^rtgssthr_grb_0.083.grib2
index ^rtgssthr_grb_0.083.idx
undef 9.999E+20
title rtgssthr_grb_0.083.grib2
dtype grib2
ydef 2160 linear -89.958000 0.083
xdef 4320 linear 0.042000 0.083000
tdef 1 linear 00Z01feb2018 1mo
zdef 1 linear 1 1
vars 1
sst   0,1,0   0,0,0  sea surface temperature [K]
endvars

—Jennifer



> On Feb 2, 2018, at 10:04 PM, Bill Reilly <Bill_Reilly at compuserve.com> wrote:
> 
> James:
> 
> Thanks for your reply.
> 
> Attached is the control file (created by Degrib) from the GRIB file: ftp://ftpprd.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/sst.20180201/rtgssthr_grb_0.083.grib2
> 
> The output fom 'q dims' is:
> 
> X is varying   Lon = -179.958 to 180.04   X = 1.00002 to 4321
> Y is varying   Lat = -89.958 to 89.9579   Y = 1.00007 to 2160
> Z is fixed     Lev = 0  Z = 1
> T is fixed     Time = 00Z01FEB2018  T = 1
> 
> Another problem is the white gap along the Greenwich Meridian, as you can see here: http://secure-web.cisco.com/1klShagusmxOl2ljtIq0xB1a58WL6eghciuLuMXRTbBkiU9zFianbONsiCD5I-y2PTKHSVmaYcvybUmgpuQ59vFAYD5cX5Oxb3ao_497WlYyjx1oIzEJd58GzNzum087LvDurkbC8wREnRMwoZPJOsbuNs98MfWYk5HOBXn5Dp-wWWuoUOvLlpXxwlQA3U86Yy8ZuczaB5cnQiDLQsstlml29f5aLrTupsYDAHHD_esZgOFgTD3NB-90jKdwg22ym-0e489MflL9bY1A6WtWEvDgQ-0ge1FkXV4dl0BULXWkEl6weDf4rGSr1oPyteCpC2uTvPUCUDc83mQkQ-xiitNejC3xjSLHJxTFOAE6NoRAuO5KHmuTiNaHv4rrKX3zyNjuKCS-2jyEOlofPn6zDclN0tiY9wtwGzc8Or_JhZNNk4VLlhcl76vx5QVgdt0Am/http%3A%2F%2Fwww.passageweather.com%2Fmaps%2Fneurope%2Fsstc.png, but that's a different problem which I'll get to afterwards.
> 
> Thanks for your help.
> 
> Bill
> 
> --
> 
> Bill Reilly
> 
> (+34) 686-110-748
> 
> bill at passageweather.com
> http://secure-web.cisco.com/1VBXmCBKOj-RAhn4LBYo7ul0_Q2nAf1ixRad8r6w2Ws2tAjVOjqFwAck9EABbOM83C00Itoz57a5YhW-gg9ifdJW-VQIghdj075tNK29OVb8VjUPojxbg5Cl5dLxshnK1zCx5pSMoCuKvSKlsVHqxGTIMYmLyU6dGthdpY_001fWXKN8rY3qirpRtMVRPaZZ_A_3WSrfzjWWWuUbbVwdMsRtLp3xG3BonNJRfsMpO371Nnu0zdzhd1ckcVmWXHiqDPMwlHKAez9Uo99TacA-VJwpdfjC2ZtsqrebAttaGQFX9yz4mvfb-m7uEHbUO9HzN67CNhOAzJ9XK4xjglu5X5aTo-RXuXbfjKnlD-HM-Ga9zO1vaH7h4hsQBGiAd5CUtCGvHqkDE5mWiFSeMmkVT277CMLYUawbVozSY9lfcx14DAsIWFHYw7Z4BC5WI9ir-/http%3A%2F%2Fwww.passageweather.com
> 
> On 03/02/2018 03:23, James T. Potemra wrote:
>> Bill,
>> 
>> Can you provide the control file?  Or the URL?  If you enter "q dims" it should show the legitimate lat/lon ranges available.  If these show a global range you should be able to plot it.
>> 
>> Jim
>> 
>> 
>> On 2/2/18 2:38 PM, Bill Reilly wrote:
>>> Hello:
>>> 
>>> I'm trying to display the NCEP global SST data using GrADS but I can't get it to display data across the 180° meridian... It will either display west of this meridian or east of it, but not both.
>>> 
>>> Using the North Pacific Ocean as an example, I want the plot to go from 110°E to 80°W.
>>> 
>>> 'set lon 110 280' only displays data WEST of 180°.
>>> 
>>> 'set lon -250 -80' only displays EAST of 180°.
>>> 
>>> 'set lon 110 -80' doesn't display anything.
>>> 
>>> 'set lon 470 640' doesn't display anything.
>>> 
>>> Does anybody have any ideas how to fix this?
>>> 
>>> Thanks,
>>> 
>>> Bill
>>> 
>>> -- 
>>> 
>>> Bill Reilly
>>> 
>>> (+34) 686-110-748
>>> 
>>> bill at passageweather.com
>>> http://secure-web.cisco.com/1VBXmCBKOj-RAhn4LBYo7ul0_Q2nAf1ixRad8r6w2Ws2tAjVOjqFwAck9EABbOM83C00Itoz57a5YhW-gg9ifdJW-VQIghdj075tNK29OVb8VjUPojxbg5Cl5dLxshnK1zCx5pSMoCuKvSKlsVHqxGTIMYmLyU6dGthdpY_001fWXKN8rY3qirpRtMVRPaZZ_A_3WSrfzjWWWuUbbVwdMsRtLp3xG3BonNJRfsMpO371Nnu0zdzhd1ckcVmWXHiqDPMwlHKAez9Uo99TacA-VJwpdfjC2ZtsqrebAttaGQFX9yz4mvfb-m7uEHbUO9HzN67CNhOAzJ9XK4xjglu5X5aTo-RXuXbfjKnlD-HM-Ga9zO1vaH7h4hsQBGiAd5CUtCGvHqkDE5mWiFSeMmkVT277CMLYUawbVozSY9lfcx14DAsIWFHYw7Z4BC5WI9ir-/http%3A%2F%2Fwww.passageweather.com
>>> 
>>> bill at brwebworks.com
>>> www.brwebworks.com
>>> 
>>> _______________________________________________
>>> gradsusr mailing list
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>> 
>> 
> 
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--
Jennifer Miletta Adams
Center for Ocean-Land-Atmosphere Studies (COLA)
George Mason University