20050223: IDV - isosurface bug or feature?

>From: Dave Santek <address@hidden>
>Organization: SSEC
>Keywords: 200502232213.j1NMDuv2029576 Time animation

Hi Dave-

>The two files have the same 11 forecast times. I'm using the Formula: 
>Simple difference a-b
>
>Then I select the 3-d grids to difference, using a single time [the same 
>time in each file]. When I do this for successive times, the isosurfaces 
>are all on a single frame. If I click the animate button, the times 
>change but nothing animates because they're all pasted into a single frame.

Yes, this is a VisAD design. If there is one time for a data object, it
acts like a base map and shows up on all times. We've discussed several
possible solutions, but each is fraught with it's own issues. You could
talk to Bill about it. ;-)

>If I do the difference with 'all times' I get:
>
>http://www.ssec.wisc.edu/~daves/idv_example.mov
>
>with an isosurface value of 45. A value of 45 is good for the middle 
>images, but I want to use a smaller value for the early images and 
>larger for the later images. My current workaround is to use pairs or 
>triplets of times to set the isosurface value, and it works just fine!

If that works for you and you don't mind doing it this way, then
I guess my work is done. ;-)  Doesn't seem like the ultimate
solution for some reason.  You might ask Tom W. for his thoughts
on this.

Don
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