Identifying STC-S footprints in SIA

[Douglas Tody]

Hi Tom -

This was discussed a while back, as well as in a splinter meeting at the
AAS a year ago (Gretchen was involved and can provide additional
detail).  The upshot was 1) this is not part of the SIA1 standard so it
must be considered an extension, until we get SIA2, 2) there is already
a Utype for this purpose and it is Char.SpatialAxis.Coverage.Support.Area,
the value being an STC string, probably with some restrictions on content.

See http://www.ivoa.net/forum/dal/2011-December/thread.html#6305
for the original discussion.

 	- Doug



On Wed, 20 Feb 2013, Tom Donaldson wrote:

> Hi All,
>
> Specifying image footprints using STC-S expressions, like the Chandra example below, has proven useful in a number of circumstances.
>
> Polygon J2000 40.57783 0.08684 40.57783 0.08048 40.66467 -0.02850 40.67115 -0.02850 40.67116 -0.02850 40.68450 -0.01787 40.68450 -0.01786 40.68450 -0.01151 40.59767 0.09748 40.59118 0.09748 40.59117 0.09747 40.57784 0.08685
>
> I was wondering if there is consensus on what UType/UCD combination should be used for such FIELDs in an SIA result.  As a provider, I'd like to use the latest/best recommendation.
>
>> From the consumer's point of view, does anyone have insight on whether there is perhaps a small array of possibilities I should look for, based on precedent or current provider behavior?
>
> Thanks!
> Tom
>
>