Hi David!
I am posting this message to the ncl-talk list becuse it might be useful
to others.
>Actually there is another alternative which would be more efficient if
>you are
>up for some Fortran programming. The NCARG low-level Vectors package
>(ultimately invoked by NCL's vector routines) does have this capability
>-- and
>there is even a simple example which you can look at if you have NCAR
>Graphics
>installed. (http://ngwww.ucar.edu/ng/ for downloads).
>
>The example is called vvex03 and assuming you have an NCARG
>installation you
>could run it with the command:
>
>ncargex vvex03.
Yes, the scattered vector plot in this example is pretty much exactly what
I am talking about. How would I use this fortran code though in my NCL
script though?
Thank you!
Cristina
>On Nov 4, 2005, at 10:42 AM, Cristina L. Archer wrote:
>
>>
>> Interesting ...
>>
>> You are saying that the most efficient way would be to create "small"
>> grids, 2 x 2, around each station with 3 missing values and only one
>> real value at the station location (actually 2 grids, one for u and one
>> for v). Then I would plot a vector from each of these small
>> grids onto a larger map that covers my all domain making sure that the
>> frame is not drawn until the last vector is done with.
>>
>>
>>> You would need to set the data coordinate extents explicitly using the
>>> 4 resources
>>> tr[Min/Max][X/Y]F.
>
>Normally the data extent is set automatically based on the min and max
>coordinate values associated with a data grid. In this case, however,
>since each
>call only contains one element of the data you would need to set the
>coordinate
>boundaries explicitly to the minimum and maximum lat and lon
>coordinates (or maybe
>slightly outside the min and max) of your vectors.
>
>>
>> What is this? I do not know about these settings.
>>
>>> If you are interested in pursuing this approach let me know. I could
>>> probably write up
>>> a little example to guide you. (I haven't ever tried this, but I'm
>>> pretty sure it could be made to work.)
>>
>> If you have time, I would certainly appreciate your guidance with this.
>>
>> Thank you so very much!
>>
>> Cristina
>>
>>
>>> -dave
>>>
>>> On Nov 3, 2005, at 3:59 PM, Cristina L. Archer wrote:
>>>
>>>>
>>>> David,
>>>>
>>>> Thank you very much for the explaination. I had the feeling that it
>>>> was
>>>> not possible yet! I just joined the ncl-talk list: should I still
>>>> post
>>>> my
>>>> question there?
>>>>
>>>> Thank you again,
>>>> Cristina
>>>>
>>>> On Thu, 3 Nov 2005, David Ian Brown wrote:
>>>>
>>>>> Hi Cristina,
>>>>>
>>>>> Unfortunately the vector plotting functions currently work for
>>>>> gridded
>>>>> data only.
>>>>> We are working on adding support for other kinds of meshes for
>>>>> vector
>>>>> data, and
>>>>> as part of that effort, it will make sense to include a facility for
>>>>> plotting scattered vectors
>>>>> specified with 4 1D arrays (lat, lon, u, v).
>>>>> Hopefully this functionality will available by next summer.
>>>>> I'm sorry we can't help you immediately.
>>>>> -dave
>>>>>
>>>>>
>>>>> On Nov 3, 2005, at 2:26 PM, Fred Clare wrote:
>>>>>
>>>>>> Dave,
>>>>>>
>>>>>> I happened to see this, even though it was discarded. I thought
>>>>>> you could give a definitive answer. I will write her and tell her
>>>>>> that she needs to sign up before her postings will appear.
>>>>>>
>>>>>> Fred
>>>>>>
>>>>>> Begin forwarded message:
>>>>>>
>>>>>>> From: ncl-talk-bounces@ucar.edu
>>>>>>> Date: November 3, 2005 12:51:59 PM MST
>>>>>>> To: ncl-talk-owner@ucar.edu
>>>>>>> Subject: Auto-discard notification
>>>>>>>
>>>>>>> The attached message has been automatically discarded.
>>>>>>>
>>>>>>> From: "Cristina L. Archer" <lozej@stanford.edu>
>>>>>>> Date: November 3, 2005 12:51:51 PM MST
>>>>>>> To: ncl-talk@ucar.edu
>>>>>>> Subject: plot vectors at stations
>>>>>>>
>>>>>>>
>>>>>>> Hi!
>>>>>>>
>>>>>>> I would like to plot wind vectors (not wind barbs) at observation
>>>>>>> sites
>>>>>>> that are scattered in a domain. I have lat and lon of the stations
>>>>>>> as
>>>>>>> well
>>>>>>> as observed u and v components. I can plot windbarbs at the
>>>>>>> stations
>>>>>>> with
>>>>>>> wmbarbmap, but I do not seem to find a way to plot simple vectors.
>>>>>>>
>>>>>>> Any help would be really appreciated.
>>>>>>>
>>>>>>> Ciao,
>>>>>>> Cristina
>>>>>>>
>>>>>>> ******************************************************************
>>>>>>> **
>>>>>>> **
>>>>>>> *********
>>>>>>> Cristina L. Archer, PhD
>>>>>>> Consulting Assistant Professor
>>>>>>> Department of Civil and Environmental Engineering Tel:
>>>>>>> 415 749 5149
>>>>>>> Stanford University Fax:
>>>>>>> 415 749 4741
>>>>>>> Stanford, CA 94305-4020 Email:
>>>>>>> lozej@stanford.edu
>>>>>>> http://www.stanford.edu/~lozej
>>>>>>> ******************************************************************
>>>>>>> **
>>>>>>> **
>>>>>>> *********
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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