20041102: 20041029: IDV - jython method for adding dataset

>From: "John C Cartwright" <address@hidden>
>Organization: NOAA/NGDC
>Keywords: 200411022201.iA2M1svV019767 IDV jython

Hi John-

>followup to my earlier message. I now have a jython method that 
>correctly plots outside of IDV. However, IDV complains about the use of 
>RealTupleType.

I've never had this problem but others have.  In some cases, 
"from visad import *" does not seem to get picked up.  Try
adding the following (in the body of the procedure):

   from visad import RealTupleType
   from visad import FunctionType
   from visad import Gridded2DSet
   from visad import FlatField

(those seem to be the ones that are needed, add others as necessary).

>Attached is samply.py which demonstrates the successful field creation 
>and listed below is the formula that complains in IDV.

Okay, thanks.

>Can you tell me what's wrong here and clarify for me when one uses the 
>methods in visad.python.JPython  methods vs. when one uses the visad.* 
>classes directly?

Here's what I got to work:

from visad import *
from visad.python.JPythonMethods import *

def generateTestField():
    row = getRealType("ROW")
    col = getRealType("COLUMN")

    domain_tuple = RealTupleType(row,col)

    pixel = getRealType("PIXEL")
    func_dom_pix = FunctionType(domain_tuple, pixel)

    NROWS = 9
    NCOLS = 18
    grid = [None]*2
    grid[0] = [None] * (NROWS*NCOLS)
    grid[1] = [None] * (NROWS*NCOLS)

    i = 0
    flat_samples = [None]
    flat_samples[0] = [None]* (NROWS*NCOLS)
    for lat in range(-90,90,20):
       for lon in range(-180,180,20):
          grid[0][i] = lon
          grid[1][i] = lat
          flat_samples[0][i] = i
          i = i+1

    domain_set = Gridded2DSet(domain_tuple,grid,NCOLS,NROWS)
    vals_ff = FlatField(func_dom_pix,domain_set)
    vals_ff.setSamples(flat_samples)
    return vals_ff

Note I did not have to do the explicit imports. If you still have
problems, try the explicit imports.

Here's what I changed:

1) I had to add in the declaration of flat_samples = [None] otherwise
I got an error.

2) You specify ROW and COLUMN as the RealTypes, but then put
lon values in for ROW and lat values for COLUMN.  That aside, I
could get this to display in the Omni control after the change
in #1.

3) To display this in the IDV, I changed:

    row = getRealType("Longitude")
    col = getRealType("Latitude")

and then displayed using one of the Plan View Displays.

>from visad import *
>from visad.python.JPythonMethods import *
>
>def generateTestField():
>    row = getRealType("ROW")
>    col = getRealType("COLUMN")
>
>    domain_tuple = RealTupleType(row,col)
>
>    pixel = getRealType("PIXEL")
>    func_dom_pix = FunctionType(domain_tuple, pixel)
>
>    NROWS = 9
>    NCOLS = 18
>    grid = [None]*2
>    grid[0] = [None] * (NROWS*NCOLS)
>    grid[1] = [None] * (NROWS*NCOLS)
>
>    i = 0
>    flat_samples[0] = [None]* (NROWS*NCOLS)
>    for lat in range(-90,90,20):
>       for lon in range(-180,180,20):
>          grid[0][i] = lon
>          grid[1][i] = lat
>          flat_samples[0][i] = i
>          i = i+1
>
>    domain_set = Gridded2DSet(domain_tuple,grid,NCOLS,NROWS)
>    vals_ff = FlatField(func_dom_pix,domain_set)
>    vals_ff.setSamples(flat_samples)
>    return vals_ff

Let me know if you have problems with what I sent.

Don
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