Re: [idvusers] Jython method to extract isosurface?

  • To: Paul Graham <meteorpaul@xxxxxxxxx>
  • Subject: Re: [idvusers] Jython method to extract isosurface?
  • From: "Don Murray (NOAA Affiliate)" <don.murray@xxxxxxxx>
  • Date: Tue, 10 Dec 2013 13:51:46 -0700
Paul-

There is no easy way/method. Even using Gridded3DSet is not simple because you would need to pass the grid domain through all the logic in the VisAD methods that compute an appropriate Gridded3DSet for the computation.

Don

On 12/10/13 1:40 PM, Paul Graham wrote:
Hi Tom/Don,

I had in mind to obtain the heights of the wet-bulb freezing level
surface, which is why I was thinking it would be nice if there was an
isosurface method that would return the heights of the surface.  I think
all one can do with folded areas is be content with a discontinuity in
any 2d representation, though a discontinuity might not be the result of
a fold.

Paul


On 11 December 2013 02:13, Don Murray (NOAA Affiliate)
<don.murray@xxxxxxxx <mailto:don.murray@xxxxxxxx>> wrote:

    All-

    Gridded3DSet would return you a geometry in VisAD coordinates and
    you could then convert those to lat/lon/alt by running them through
    the MapProjectionDisplay's coordinate system (fromReference), I
    would presume.  But tom's point is valid in that you can't always
    map an isosurface to a 2D surface.  Even a "simple" field like
    temperature might have folds where there are inversions.

    Don


    On 12/10/13 8:08 AM, Tommy Jasmin wrote:

        On 12/10/13 8:52 AM, Tom Whittaker wrote:

            Paul -- I don't know of anything off-hand.  One issue I see
            is if
            there is a fold in the isosurface, a 2D representation is
            impossible.
            For example, think of an isosurface of wind speed for, say,
            the 40kt
            isosurface -- they would be "tubes" and "bubbles"...

            tom

            On Mon, Dec 9, 2013 at 11:47 PM, Paul Graham
            <meteorpaul@xxxxxxxxx <mailto:meteorpaul@xxxxxxxxx>>
            wrote:

                Hi IDV'ers,

                I'm interested to know if there is a way to extract an
                isosurface
                from a 3d
                gridded field and store it as a 2d grid of isosurface
                heights for
                display
                or other purposes, using an IDV Jython script?

                Any help is appreciated.

                Thanks,

                Paul
                _________________________________________________


        Hi guys - you are probably both aware but just to be sure, the VisAD
        Gridded3DSet
        class does have methods to extract both isosurfaces and isolines :

        http://www.ssec.wisc.edu/__visad-docs/javadoc/visad/__Gridded3DSet.html
        <http://www.ssec.wisc.edu/visad-docs/javadoc/visad/Gridded3DSet.html>


    --
    Don Murray
    NOAA/ESRL/PSD and CU-CIRES
    303-497-3596
    http://www.esrl.noaa.gov/psd/__people/don.murray/
    <http://www.esrl.noaa.gov/psd/people/don.murray/>


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--
Paul Graham
Email: meteorpaul@xxxxxxxxx <mailto:meteorpaul@xxxxxxxxx>
Mobile: 0403003784

--
Don Murray
NOAA/ESRL/PSD and CU-CIRES
303-497-3596
http://www.esrl.noaa.gov/psd/people/don.murray/