Re: Why wind vectors could not be plotted in a sub-area with the same ncl codes?

Hi Ed,

There's something I don't understand about your file.

Why does your data have rlat0/rlon0 coordinate arrays, which I would have thought would be lat/lon arrays, yet you are using tlat and tlon on the file?

Also, where did you get the map projection parameters from (i.e. the two parallels)? I think you have a rotated grid, and the projection may not be set correctly for your data.

I noticed that the Corners resources in your two scripts were slightly different. If I use the values from the plot_2.ncl file in the plot_1.ncl file, then I see more vectors.

However, there is a strange seam line in your contour plot, like things are not lining up quite right. This is why I think there's something wrong with the map projection used.

Please see the example on our rotated lat-lon grid page:

http://www.ncl.ucar.edu/Applications/rotatedltln.shtml

Note that the example uses values on the file to get the map projection exactly right, without using hard-coded numbers. You may want to try something like this, if you have all the necessary map parameter information on the file. I didn't see it on the file you gave me, but maybe the original file has it?

--Mary

On Jul 9, 2012, at 4:16 PM, Yang Yang wrote:

> Hi Mary:
>
> I have sent you my data via the previous email. Attached please find the two pics plotted by the two ncl codes.
>
> Please let me know if you have not received the data.
>
> Cheers!
>
> Ed
>
>
> --- On Tue, 7/10/12, Mary Haley <haley@ucar.edu> wrote:
>
>> From: Mary Haley <haley@ucar.edu>
>> Subject: Re: Why wind vectors could not be plotted in a sub-area with the same ncl codes?
>> To: "Yang Yang" <yang123yang@yahoo.com>
>> Cc: "Dennis Shea" <shea@ucar.edu>
>> Date: Tuesday, July 10, 2012, 1:22 AM
>> Hi,
>>
>> Still no luck:
>>
>> -rw-rw-r-- 1 haley CIT\Domain Users
>> 203812153 Jul 9 11:19 test.nc.gz
>>
>> I think the file is getting truncated every time you upload
>> it. Do you have some place else you can put it,
>> or can you try making it smaller? Perhaps you can write only
>> the variables needed for plotting to another file?
>>
>> --Mary
>>
>>
>> On Jul 8, 2012, at 3:40 PM, Yang Yang wrote:
>>
>>> Hi Mary and Dennis:
>>>
>>> Thank you very much for your help. I checked the
>> compressed file again and had the same problem as yours.
>> Sorry for the problem.
>>>
>>> I recompressed the file, which should be right this
>> time.
>>>
>>> yangy@thotter:TEMP/ $ ls -il test.nc.gz
>>> 3785158064 -rw-r--r-- 1 yangy niwa-users 308594775
>> 2012-07-09 09:14 test.nc.gz
>>>
>>> I ftped the file again. If you cannot find a file named
>> test.nc.gz or the file size is different, would you please
>> let me know? This file is exactly the same file I used to
>> plot.
>>>
>>> Cheers!
>>>
>>> Ed
>>> --- On Fri, 7/6/12, Mary Haley <haley@ucar.edu>
>> wrote:
>>>
>>>> From: Mary Haley <haley@ucar.edu>
>>>> Subject: Re: Why wind vectors could not
>> be plotted in a sub-area with the same ncl codes?
>>>> To: "Yang Yang" <yang123yang@yahoo.com>
>>>> Cc: "Dennis Shea" <shea@ucar.edu>
>>>> Date: Friday, July 6, 2012, 10:08 PM
>>>> Dear Ed,
>>>>
>>>> I downloaded your file, but when I tried to unzip
>> it, I got
>>>> the error:
>>>>
>>>> % gunzip xadala_pi00002011050215_utc.nc.gz
>>>>
>>>> gzip: xadala_pi00002011050215_utc.nc.gz: unexpected
>> end of
>>>> file
>>>>
>>>> The file is 205103998 bytes. Can you
>> double-check that
>>>> the file is valid on your end, and put it on
>>>> anonymous ftp again if possible?
>>>>
>>>> Thanks,
>>>>
>>>> --Mary
>>>>
>>>> On Jul 5, 2012, at 10:57 PM, Yang Yang wrote:
>>>>
>>>>> Hi Dennis:
>>>>>
>>>>> Thanks for your help.
>>>>>
>>>>> I have ftped the file to the specified
>> directory. It is
>>>> a compressed file:
>> xadala_pi00002011050215_utc.nc.gz
>>>>>
>>>>> Would you please let me know if you cannot find
>> the
>>>> file? Thanks!
>>>>>
>>>>> Ed
>>>>>
>>>>> --- On Fri, 7/6/12, Dennis Shea <shea@ucar.edu>
>>>> wrote:
>>>>>
>>>>>> From: Dennis Shea <shea@ucar.edu>
>>>>>> Subject: Re: Why wind vectors
>> could not
>>>> be plotted in a sub-area with the same ncl codes?
>>>>>> To: "Yang Yang" <yang123yang@yahoo.com>
>>>>>> Cc: ncl-talk@ucar.edu
>>>>>> Date: Friday, July 6, 2012, 7:22 AM
>>>>>> Nothing obviously wrong see 'diff'
>>>>>> below'.
>>>>>>
>>>>>>
>>>>>> It might be best to send the file to:
>>>>>>
>>>>>> ftp ftp.cgd.ucar.edu
>>>>>> anonymous
>>>>>> <use your email address for the
>> password>
>>>>>> cd incoming
>>>>>> put xadala_pi00002011050215_utc.nc
>>>>>> quit
>>>>>>
>>>>>> Send email to ncl-talk
>>>>>> after you have successfully completed the
>>>> transfer.
>>>>>>
>>>>>> ================================
>>>>>> Rather than a double do loop
>>>>>>
>>>>>> do i=100, 500
>>>>>> do j=100, 500
>>>>>>
>>>>>>
>> xx=(v10m(i,j+1)-v10m(i,j-1))/200.
>>>>>>
>>>>>>
>> yy=(u10m(i+1,j)-u10m(i-1,j))/200.
>>>>>> vor(i,j)=xx-yy
>>>>>> end do
>>>>>> end do
>>>>>>
>>>>>> Why not use the builtin func
>>>>>> dd = 200.0
>>>>>> xx =
>>>> center_finite_diff_n
>>>>>> (v10m,200,False,0, 1)
>>>>>> yy =
>>>> center_finite_diff_n
>>>>>> (u10m,200,False,0, 0)
>>>>>> vor = xx-yy
>>>>>> ================================
>>>>>> %> diff plot_1.ncl plot_2.ncl
>>>>>>
>>>>>> 91c91
>>>>>> <
>> res1@gsnLeftString =
>>>> "Plot_1 "
>>>>>> ---
>>>>>>>
>> res1@gsnLeftString =
>>>> "Plot_2 "
>>>>>> 129c129
>>>>>> < wks =
>> gsn_open_wks
>>>>>> ("eps","plot_1")
>> ; open
>>>>>> workstation
>>>>>> ---
>>>>>>> wks =
>> gsn_open_wks
>>>>>> ("eps","plot_2")
>> ; open
>>>>>> workstation
>>>>>> 139,142c139,142
>>>>>>
>>>>
>> < res1@mpLeftCornerLatF
>>>>>> = -36.85
>>>>>>
>>>>
>> < res1@mpLeftCornerLonF
>>>>>> = 174.54
>>>>>>
>>>>
>> < res1@mpRightCornerLatF
>>>>>> = -36.6
>>>>>>
>>>>
>> < res1@mpRightCornerLonF
>>>>>> = 174.85
>>>>>> ---
>>>>>>>
>>>> res1@mpLeftCornerLatF
>>>>>> = -36.75
>>>>>>>
>>>> res1@mpLeftCornerLonF
>>>>>> = 174.64
>>>>>>>
>>>> res1@mpRightCornerLatF
>>>>>> = -36.65
>>>>>>>
>>>> res1@mpRightCornerLonF
>>>>>> = 174.75
>>>>>> 149c149
>>>>>> < inc = 10
>>>>
>>>>>>
>>
>>>> ;
>>>>>> plot at every "inc" grid point
>>>>>> ---
>>>>>>> inc = 2
>>
>>>>
>>>>>>
>>
>>>> ;
>>>>>> plot at every "inc" grid point
>>>>>> =================================
>>>>>>
>>>>>>
>>>>>> On 7/5/12 3:44 PM, Yang Yang wrote:
>>>>>>> Hi:
>>>>>>>
>>>>>>> I posted the issue two days ago.
>> Perhaps I
>>>> didn't
>>>>>> describe it well. I have not received any
>> response.
>>>> So I
>>>>>> repost it here. Sorry!
>>>>>>>
>>>>>>> I used the same ncl codes to plot wind
>> vectors
>>>> in an
>>>>>> area (~30x30km) and a sub-area (~10x10km)
>> of it.
>>>> The only
>>>>>> differences are the parameters controlling
>> the area
>>>> to plot.
>>>>>> However, the wind vectors can be plotted
>> for the
>>>> large area
>>>>>> (this means my data are OK) but not on the
>>>> sub-area. Can
>>>>>> anyone help me fix the problem?
>>>>>>>
>>>>>>> plot_1.png was plotted by plot_1.ncl
>> for the
>>>> large
>>>>>> area. plot_2.png was plotted for the
>> sub-area by
>>>>>> plot_2.ncl.The resolution of the data is
>> 100m.
>>>>>>>
>>>>>>> Thank you very much!
>>>>>>>
>>>>>>> Ed
>>>>>>>
>>>>>>> --- On Wed, 7/4/12, Yang Yang<yang123yang@yahoo.com>
>>>>
>>>>>> wrote:
>>>>>>>
>>>>>>>> From: Yang Yang<yang123yang@yahoo.com>
>>>>>>>> Subject: Odd plot of
>> wind
>>>> vectors
>>>>>>>> To: ncl-talk@ucar.edu
>>>>>>>> Date: Wednesday, July 4, 2012, 8:14
>> AM
>>>>>>>> Hi:
>>>>>>>>
>>>>>>>> I have a regional model output
>> (100m
>>>> resolution).
>>>>>> When I
>>>>>>>> ploted an area about 30x30km
>> (plot_1.png
>>>> attached)
>>>>>> using
>>>>>>>> plot_1.ncl, the plot seems OK.
>> However,
>>>> when I
>>>>>> tried to plot
>>>>>>>> an area about 10x10km within the
>> 30x30km
>>>> area, the
>>>>>> plotted
>>>>>>>> wind vectors are quite odd
>> (plot_2.png by
>>>>>> plot_2.ncl), and
>>>>>>>> wind vectors were not plotted in
>> most
>>>> areas. Can
>>>>>> anyone help
>>>>>>>> me fix the problem? Thanks!
>>>>>>>>
>>>>>>>> Ed
>>>>>>>> -----Inline Attachment
>> Follows-----
>>>>>>>>
>>>>>>>>
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Received on Wed Jul 11 11:09:05 2012