Boxes and Polygons in ADQL/STC. Questions and recommendation.

[John Good]

Whether it is a padded image region or a bounding polygon
around a set of images, the point was that this is a common
general use pattern and definitely not a RECT.  Holes I would
expect are most commonly handled by in a "second pass" on
a set of records identified by a simpler query but again are
even less pertinent to the issue of the ubiquity of RECT
queries. 

- John



Rob Seaman wrote:
> The use case "people trying to get sources that match an image" is a 
> bit loose.  For instance, I wrote an IRAF-based astrometry tool to 
> query the HST GSC for sources overlapping an image.  A parameter 
> expands the boundary of the image in all directions (in pixels or 
> arcsecs).  One obvious reason for this is that the tool is being used 
> on input images with only poorly known WCS information.  Another 
> reason, however, is that typical usage would be applied to a stack of 
> images with differing offsets on the sky.  The query is used to 
> generate an intermediate catalog applicable to several frames.
>
> In any event, a question here is whether a particular query is 
> required to be complete against the image, but may include some 
> fraction of hits outside the boundaries of the image - or whether the 
> query must be restricted for some reason to hits guaranteed to to rest 
> only within the edges (straight, curved or otherwise) of a particular 
> area (and then must the query be complete?).  (And what about holes 
> that might be cut into the image, etc and so forth?)
>
> Rob
> ---
> On Oct 24, 2009, at 11:56 AM, John Good wrote:
>
>> Roy -
>>
>>> My point is that I suspect 90% of region queries will, in reality, 
>>> be RECT or CONE. We should make sure this works well in the 
>>> prototypes, perhaps delay the more complex region implementation 
>>> until these two work well?
>> Not true.  Cone is probably the most common but the next most common
>> is people trying to get sources that match an image, which is hardly 
>> ever
>> a RECT (and is in fact usually more like a rotated BOX).
>>
>> - John