Re: PyNGL vector_map with irregular grid

Unfortunately we have not yet implemented vector plotting on
triangular meshes for
NCL or PyNGL. It is now available at lower-level NCAR Graphics
level, and
providing an interface to this capability for NCL and PyNGL is
definitely high on our priority list.
This will allow plotting of vector fields specified using 1D arrays.
  -dave

On Dec 6, 2007, at 7:13 PM, Thomas Shay wrote:

> On Dec 6, 2007, at 8:46 PM, Dennis Shea wrote:
>
>> FYI: There is a pyngl-talk mailing list [pyngl-talk_at_ucar.edu]
>>
>> The leap from NCL graphics to PYNGL graphics is not
>> that great. Look at:
>> http://www.ncl.ucar.edu/Applications/trimesh.shtml
>> for the appropriate resources.
>>
>> ===============================
>> The pyngl solution is at:
>> http://www.pyngl.ucar.edu/Examples/gallery.shtml
>> See "Contouring on non-rectangular Grids"
>>
>> Good luck
>
> Thanks for that, although I have already been able to make contour
> plots on this grid. My problem is with vector plots specifically,
> in which the u and v need to be 2-d arrays. This is not the case
> with contour plots, where the scalar field can be specified as
> either a 1-d or a 2-d array.
>
> From the documentation for Ngl.contour_map:
>
> data
> The data to contour. data can be a two-dimensional NumPy array or
> NumPy masked array (ny x nx), or a one-dimensional array that is
> accompanied by one-dimensional coordinate arrays of the same length
> (see description below).
>
> From the documentation for Ngl.vector_map:
>
> u, v
> The U and V components of the vectors. u and v should be two-
> dimensional NumPy arrays or NumPy masked arrays (dimensioned ny x nx).
>
>
>
>> Thomas J. Shay wrote:
>>> I am using the PyNGL interface for this problem.
>>>
>>> I'm trying to figure out how to make a vector/map plot
>>> (Ngl.vector_map) with the output of a finite element model. The
>>> lon, lat, u, and v are 1-d arrays, with each element
>>> corresponding to a node in the mesh. According to the
>>> documentation of Ngl.vector_map, the u and v (and presumably lon
>>> and lat) need to be 2-d arrays. My mesh has irregular triangle
>>> elements and the boundary is also irregular (has a real
>>> coastline, etc.), so it's not clear how to turn u, v, etc. into 2-
>>> d arrays.
>>>
>>> Can anyone point me in the right direction?
>>>
>>> Thanks,
>>>
>>> Tom
>>>
>>>
>>
>>
>
> --
> Thomas Shay
> UNC Chapel Hill
> tshay_at_email.unc.edu
>
>
>
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> ncl-talk_at_ucar.edu
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Received on Thu Dec 06 2007 - 20:46:21 MST