IVOA Footprint Service Protocol

[Arnold Rots]

The correct reference for [2] is:
> [2] STC-S (A. Rots): 
> http://www.ivoa.net/Documents/latest/STC-S.html

  - Arnold

Roy Williams wrote:
> Keith (as DAL chair)
> 
> I am writing to discharge a task I have been given by the NVO Team 
> Meeting, which is just finishing this afternoon. We have had a 
> discussion of Footprint formats and Footprint services, and we would 
> like you to start a new activity within DAL to standardize these 
> services across all footprint servers.
> 
> Perhaps we could start by asking for proposals from DAL group members 
> about how these protocols might look? Below are some notes and URLs that 
> I hope will set the scope. I am assuming that everyone who wants to 
> participate will be on the DAL mailing list.
> 
> Roy
> 
> ------------------------------------------
> 
> -- How should footprints be described? Presumably by a text 
> serialization in the IVOA standard [1] or non-standard [2],[3] formats. 
> Or through a reference to a footprint, by an IVO or http reference. Or 
> as the footprint that belongs to a survey (eg. "the SDSS footprint"). 
> What other ways are there to get a "handle" on a sky footprint?
> 
> -- What methods can be applied to a footprint? Intersection, Union I 
> would think. Find the area on the celestial sphere. Does it contain a 
> given point? Which of a set of points does it contain? Methods to 
> serialize footprints, perhaps to make images of them, or to make 
> polygons on Google Sky?
> 
> -- What services are already prototyped? I know of the Aladin system [4] 
> and the JHU services [5]. Who else is involved in sky footprint work 
> besides these?
> 
> [1] IVOA STC: http://www.ivoa.net/Documents/latest/STC-Model.html
> [2] Linear STC (A. Rots): 
> http://www.ivoa.net/Documents/latest/LinearSTC.html
> [3] VOTable STC (Aladin group): 
> http://www.ivoa.net/Documents/latest/Footprint.html
> [4] Aladin: http://aladin.u-strasbg.fr/
> [5] JHU footprint services: http://voservices.net/footprint/
> 
> -- 
> 
> California Institute of Technology
> 626 395 3670
> 
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Arnold H. Rots                                Chandra X-ray Science Center
Smithsonian Astrophysical Observatory                tel:  +1 617 496 7701
60 Garden Street, MS 67                              fax:  +1 617 495 7356
Cambridge, MA 02138                             arots at head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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