WD-DALI-1.1

[Patrick Dowler]

On  a somewhat more speculative nature, I have added a subsection that
defines the polymorphic "region" xtype. There is not yet consensus on
whether we should do this, but the values described show up in
SIA-2.0, SODA-1.0, and is essentially what we also use in TAP-1.0
(region columns sans additional metadata in the value)*.

The diff so you can see what this might look like:

https://volute.g-vo.org/viewvc/volute/trunk/projects/dal/DALI/DALI.tex?r1=3530&r2=3531


* resolves the issue of whether or not the adql: prefix should be used
in tap_schema (result: do not use) consistent with dicussions from
awhile back (iirc) and I feel makes it feasible for TAP services to
transition from "region" to "polygon" in the tap_schema. So, in
standard DALI fashion this is in some sense codifying current practice
from TAP-1.0

-- 
Patrick Dowler
Canadian Astronomy Data Centre
Victoria, BC, Canada