[gradsusr] ctl file for irregular lon and lat dimension

Sat Jun 22 05:22:51 EDT 2019

Dear Mr. Jeff

Much thanks for the answer.

I will try it.

Best regards
wendi

On Sat, Jun 22, 2019 at 7:00 AM Jeff Duda <jeffduda319 at gmail.com> wrote:

> Wendi,
> Here is the header of a control file I am using to plot WRF output:
>
> dset
> /lfs1/projects/wrfruc/jdduda/WRF_HRRRX/run/wrfout_d01_2019-04-%d2_%h2_00_00
>
> dtype netcdf
>
> undef -9999
>
> options template
>
> title  OUTPUT FROM WRF V3.9pre#2 MODEL - scalar fields - by Jeff Duda
>
> pdef 1799 1059 lcc   21.13812 -122.71953 1 1   38.50000   38.50000  -97.50000
> 3000.00000 3000.00000
>
> xdef  1799 linear -134.09862 0.04068774
>
> ydef  1059 linear   21.13812 0.02972887
>
> zdef 50 linear 1 1.0
>
> tdef 19 linear 17Z25APR2019 1HR
>
> VARS  252
>
>
> The domain is on a Lambert conformal projection, as can be determined from
> examining the PDEF line. To determine the delta-x and delta-y values, I
> dumped out the latitude and longitude values from the output file. Knowing
> how a Lambert projection works, I know the minimum longitude value occurs
> at the grid point of the topmost row and leftmost column (NW corner of the
> domain), and the maximum occurs on the other end of that same row. The
> minimum longitude occurs either in the SW or SE corner (depending on what
> you set for the standard and center lons/lats), but I knew from my setup
> that either the SW or SE corner would suffice. The maximum latitude occurs
> halfway through the topmost row.
>
>
> So I obtained the max and min lat and lon values, took the difference
> between them , then divided by either 1799 or 1059, which happens to be nx
> and ny, respectively, in my WRF file (but you can technically use any
> values you want).
>
>
> Jeff Duda
>
> On Thu, Jun 20, 2019 at 7:06 PM wendi harjupa <wendiharjupa at gmail.com>
> wrote:
>
>> Dear Mr. Jeff,
>>
>> Thank you very much for your response.
>>
>> I am very sorry for more question,
>> Would you mind to give me an example for your explanation?
>> or it ever asked before by other members, would you share me the link?
>>
>> Best regards,
>> wendi
>>
>> On Fri, Jun 21, 2019 at 2:27 AM Jeff Duda <jeffduda319 at gmail.com> wrote:
>>
>>> Keep in mind that it's generally a good idea (but is not strictly
>>> required) that the following relationship is held in the XDEF and YDEF
>>> lines:
>>>
>>> max_x = min_x + dx*nx
>>> max_y = min_y + dy*ny
>>>
>>> What I usually do is find the maximum and minimum latitudes and
>>> longitudes anywhere in the geographic domain and then divide the difference
>>> in those by whatever you set for NX or NY. Use that as the step value. XDEF
>>> and YDEF are largely cosmetic for irregular grids, though. What is most
>>> important for getting your data to show up correctly is having a PDEF entry
>>> with the correct values for whatever your projection is. If your data are
>>> not projected in a way that Grads can support then I'm not sure you can do
>>> this using GrADS.
>>>
>>> Jeff Duda
>>>
>>> On Thu, Jun 20, 2019 at 1:46 AM wendi harjupa <wendiharjupa at gmail.com>
>>> wrote:
>>>
>>>> Dear GrADS users,
>>>>
>>>> I need your help with this problem.
>>>> I have two-dimensional data, which have no linear resolution, such
>>>> below;
>>>>
>>>> 1. The first, second, third and the last coordinate longitude data are
>>>> 21.2887,  121.29860, 121.30840 and 148.76140, respectively.
>>>> 2. The first, second, third and the last coordinate latitude data are
>>>> 22.70906, 22.70909, 22.70911 and
>>>> 46.19549, respectively.
>>>>
>>>> I want to make the control file for the data to plot it by grads,
>>>>
>>>> XDEF LEVEL 2800 121.28870  XXXX
>>>> YDEF LEVEL 2400 22.70906 YYYY
>>>>
>>>> What number should I use to change XXXX and YYYY?
>>>> and is there special command should I use to handle the irregular
>>>> spatial resolution?
>>>>
>>>> Very appreciate for your help.
>>>> Thank you very much.
>>>> Best regards,
>>>> wendi
>>>>
>>>>
>>>>
>>>>
>>>> On Wed, Jun 19, 2019 at 9:17 PM wendi harjupa <wendiharjupa at gmail.com>
>>>> wrote:
>>>>
>>>>> Dear GrADS user,
>>>>>
>>>>> I want to plot the data which has irregular lon and lat...
>>>>> I donot want to interpolate the data, so I just want to plot it as the
>>>>> original data.
>>>>>
>>>>> My question is how to make the control file for the irregular lon and
>>>>> lat data.
>>>>> I attach two data through this email,
>>>>> 1. asci data which shows the different of lon and lat of the data.
>>>>> 2. Binary format data of the asci data.
>>>>>
>>>>> Thank you very much for your help.
>>>>>
>>>>> best regards
>>>>> wendi
>>>>>  RDCA20150803_0305.bin
>>>>> <https://drive.google.com/file/d/1HDCQXO30JwIRCaxTL-H1pf6eibRvhTpp/view?usp=drive_web>
>>>>>  RDCA20150803_0305.txt
>>>>> <https://drive.google.com/file/d/1l0vSZLO0Z21aBlfuMLF2UJM02m0kXTtC/view?usp=drive_web>
>>>>>
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>>>>
>>>
>>>
>>> --
>>> Jeff Duda, Research Scientist
>>> University of Colorado Boulder
>>> Cooperative Institute for Research in Environmental Sciences
>>> NOAA/OAR/ESRL/Global Systems Division
>>> Boulder, CO
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>> _______________________________________________
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>
>
> --
> Jeff Duda, Research Scientist
> University of Colorado Boulder
> Cooperative Institute for Research in Environmental Sciences
> NOAA/OAR/ESRL/Global Systems Division
> Boulder, CO
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
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