[IDV #AVV-925136]: Temperature from GRIB message over topography error.

["Unidata IDV Support" <support-idv@xxxxxxxxxxxxxxxx>]

Hi-

> Full Name: Hrobjartur Thorsteinsson
> Email Address: hroi@xxxxxxxx
> Organization: Icelandic Met Office
> Package Version: 2.4 build date:2007-12-20 16:34 UTC
> Operating System: Linux
> Hardware: Java: home: /nfs/blade03/home/hroi/local/share/IDV_2.4/jre version: 1.5.0_11 j3d:1.3.1
> Description of problem: Creating display: Color-Shaded Plan View Over Topography
> org.python.core.PyException

The problem is that the "2D" field is really a 3D field at a fixed height.
We categorize fields with only one level as "2D".  So, the error is indicating
that the IDV couldn't  combine the 2D and 3D fields.  I've put in a fix
for this which will show up in the next nightly build.

However, that still won't allow you to create the display you want.  For
these two files, the ranges of the longitudes are different.  The topography
field has longitudes going from -180 to 180, but the grid has longitude
values from  334.0 to 348.0.  

Now one might say "but 334 is the same as -26" so the IDV should be able
to figure it out.  The underlying resampling code makes no assumptions about
the units in this case, it just knows that -26 is outside the range of 334
to 348 so does find any matching points.  The same sampling code is used for
non lat/lon values (like grid numbers or km along the projection) so it's
kind of dumb when it comes to lat/lon.  The only solution would be to
rewrite the topo file with longitudes in the range of 0 to 360 or the GRIB 
file with longitudes in the range of -180 to 180. 

Don Murray

> ******************
> Stack trace:
> Traceback (innermost last):
> File "<string>", line 1, in ?
> at visad.Set.<init>(Set.java:148)
> at visad.SimpleSet.<init>(SimpleSet.java:58)
> at visad.SampledSet.<init>(SampledSet.java:47)
> at visad.GriddedSet.<init>(GriddedSet.java:72)
> at visad.Gridded2DSet.<init>(Gridded2DSet.java:72)
> at visad.Gridded2DSet.<init>(Gridded2DSet.java:56)
> at ucar.unidata.data.grid.DerivedGridFactory.create2DTopography(DerivedGridFactory.java:613)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at java.lang.reflect.Method.invoke(Method.java:585)
> 
> visad.UnitException: visad.UnitException: Set: units dimension 2 does not match Domain dimension 3
> 
> 
> 


Ticket Details
===================
Ticket ID: AVV-925136
Department: Support IDV
Priority: Normal
Status: Open