STC Version 1.20

I just submitted STC version 1.20 to the IVOA repository. It includes updates to the Working Draft, the STC-XML document, the three schema files, and a new document: Linear STC. It can be previewed through the NVO project page:

        http://us-vo.org/projects/project.cfm?ID=62

Note that the versions of the schemata on my private web page have a schemaLocation, whereas the ones submitted to the IVOA site do not.

Most of the changes will not be very noticeable and fall in the categories:

• Changes to force schema validation by Xerces-J2; this has resulted in some obfuscation of the schema but does not really affect any instances (I think)
• SpaceFrames updates and clarifications; this mainly affects planetary systems
• Time: added timescale TEB (Barycentric Ephemeris Time), restricted the use of ISOTime to > 0001-01-01 (since someone had the audacity to put a minus sign in front)
• Brought units in compliance with FITS standard
• Require Polygons to have sides < 180 deg, consistent with AST rules
• Added Box shape
• Revised the definition of position angle

I append the list of changes from version 1.10

Linear STC is a "command line" implementation of STC, with an eye toward ADQL and human readability; read the first three pages of the document if you are interested.

Enjoy,

• Arnold

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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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Appendix D - Changes from Previous Versions

>From V1.10 to V1.20:

• Distinguished LSRK and LSRD; replaced SUPER_GALACTIC_CENTER by LOCAL_GROUP_CENTER
• Added Box shape to Region
• Require polygon sides to be less than 180°; added explanation on defining inside and outside
• Added LinearSTC implementation
• Subtle changes to the schemata to force validation under Xerces-J2; this did not change anything but made the schemata a little uglier
• Changed units "micron" and "A" to "um" and "Angstrom", respectively, consistent with the FITS standard
• Added timescale TEB, with references
• Added warning on use of ISOTime and restricted its use explicitly
• Added an explicit definition of Position Angle; in the XML implementation it is now an element, rather than an attribute (see, e.g., Ellipse)
• Added a reference spheroid to GEO_D, changed GEO to GEO_C
• Added an explicit discussion of planetographic and planetocentric coordinate systems, with references, as well as a discussion of right-handed and left-handed systems
• Removed GEOGRAPHIC CoordFlavor, replacing it by 3-dimensional SPHERICAL, and added POLAR