20041116: Problem with Altitude Slice of ocean_s_coordinate

>From: Rich Signell <address@hidden>
>Organization: USGS
>Keywords: 200411162151.iAGLpe7j024159 IDV slice at level

Hi Rich-

>I'm having some strange behavior when using slicing a
>ocean_s_coordinate field at a constant z-level and
>displaying a "color-shaded plan view" display.  The
>resulting display is banded and only extends part way
>across my domain.  Quite strange and striking looking!
>See the distinct bands along the Maine Coast in the
>attached image from the Gulf of Maine.

This may be related to a problem we've found with some similar
grids.

>The Jython I'm using is:
>
>
># Slice at fixed z level
>#
>def getSliceAtAltitude(fieldimpl, alt, unit="m") :
>  """ extract a 2D horizontal slice from a 3D grid at the given altitude
>      level is a real number; if unit is supplied, it must
>      be compatible with meters (ft, fathoms, etc)
>      param fieldimpl is a VisAD FieldImpl which may have
>      one or more time steps.  """
>  #import methods from
>  import ucar.unidata.data.grid.GridUtil as gu
>  from visad import RealType
>  from visad import Real
>  import visad.data.units.Parser as parser
>  alt = float(alt)
>  unit = parser.parse(str(unit))
>  altitude = Real(RealType.Altitude, alt, unit)
>  ff = gu.sliceAtLevel(fieldimpl, altitude)
>  return ff

This is now in the core for the next release.

>I'm attaching a bundle and hoping that you have a chance
>to check out whether you have the same problem and what it might be.
>I'm also attaching my tarred up ~/.metapps/DefaultIdv in case you
>want to look at my jython & formulas.

The bundle does not point to any data (just has displays).  What dataset 
are you using and what altitude are you slicing at?  Can you put
a bundle out that has a pointer to data on a remote server?

Thanks.

Don
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