Re: Tuple vs. FieldImpl displays

• To: Bill Hibbard <billh@xxxxxxxxxxxxx>
• Subject: Re: Tuple vs. FieldImpl displays
• From: Don Murray <dmurray@xxxxxxxxxxxxxxxx>
• Date: Mon, 18 Aug 2003 08:43:54 -0600

Hi Bill-

Bill Hibbard wrote:

This may be a bug. As long as both FlatFields in the Tuple
have MathTypes whose RealTypes are appropriately mapped
they should both be visible.

The FlatFields in the Tuple are the same objects as the
FlatFields in the FieldImpl, so they should both show.
The example is pretty simple and should be helpful in
tracking the bug down.

The deal with CoordinateSystems (as with Units) is that
the CS in the actual data may use a different CS than
the RealTupleType, as long as they both have the same
reference RealTupleType. That it, in:

  (index -> ((UTM_easting, UTM_northing) -> (Altitude)))

if the RealTupleType (UTM_easting, UTM_northing) has a
CS with reference (Latitude, Longitude) then all the
FlatFields in the range of index must have CS's with
reference (Latitude, Longitude). The code in FieldImpl
doesn't check to make sure the RealTupleType and data
CS's have the same class, only the same reference.

This is very much a feature, to allow things like
satellite navigation and pressure coordinates to change
over time.

Thanks for the background on how this all works.

Don
*************************************************************
Don Murray                               UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx                        P.O. Box 3000
(303) 497-8628                              Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
*************************************************************

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    • From: Bill Hibbard