[gradsusr] plotting over 0E from netCDF

[Charles Seman - NOAA Federal]

Cathy,

To elaborate a bit more on what Jim has said.  I have a netCDF dataset 
with 480 longitudes: 0., 0.75, ... , 359.25 (uniform dlon) and am able 
to plot over Africa using the commands you gave below.  It appears from 
your lon listing that the dlon are not uniform... For example, dlon = 
0.7031252 for the first grid box, but dlon = 0.7031248 for the second 
grid box, and so on, and dlon = 0.7031 for the last grid box (dlon = 
359.297-358.5939 = 0.7031), so it appears that GrADS doesn't "wrap" 
around 0/360.  Don't know if this is the reason, but see if you can find 
a dataset with a uniform longitude spacing, and try with that.

Chuck

On 06/29/2016 01:49 PM, James T. Potemra wrote:
> Kathy,
>
> I think the problem is you don't have a continuous grid across 0/360.
> If your data were, for example, evenly spaced and you had a single value
> at 360 then you could do 340 to 415.  In this case you don't have any
> longitudes greater than 360 defined.  You might need to either regrid
> or use an external tool (e.g., nco) to redefine longitude.  Of course you
> could also use "parea" to plot the western side and eastern sides
> individually.
>
> Jim
>
> On 6/29/16 4:57 AM, Cathy Smith (NOAA Affiliate) wrote:
>> Hi all
>> This should be an easy question but I'm stumped. I'm trying to plot
>> Africa (20W to 55E). the file I'm plotting from is netCDF and the
>> longitudes are 0 to 359.27
>>
>> e.g.
>>    lon = 0, 0.7031252, 1.40625, 2.109376, 2.812501, 3.515626, 4.218751,
>>       4.921877, 5.625002, 6.328127, 7.031252, 7.734378, 8.437503, 9.140628,
>>       9.843754, 10.54688, 11.25, 11.95313, 12.65625, 13.35938, 14.0625,
>> ......
>>       354.3751, 355.0782, 355.7814, 356.4845, 357.1876, 357.8907, 358.5939,
>>       359.297 ;
>>
>> my grads code has
>>
>>    if( proj = 'africa' )
>>       'set mproj latlon'
>>       'set mpdset mres'
>>       'set lat -40 45'
>>       'set lon -20 55'
>>       'set grid on'
>>       'set frame on'
>>       'set ylint 5'
>>        istate=0
>>     endif
>>
>> which plots the data from 0 to 55 only and not the data between 340 and 360.
>>
>> I also tried 340 to 415 instead of -20 to 55 and that plotted the data
>> from 340 to 0 and not 0 to 55.
>>
>> What am I doing wrong? I know this can be done in GrADS.
>>
>> Thanks
>> Cathy
>>
>
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-- 

Please note that Charles.Seman at noaa.gov should be considered my NOAA
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