Information on Service 'STC utype generator'

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Service Documentation

This service lets you convert between various representations of IVOA space-time coordinate (STC) data model instances:

• STC-S as discussed below
• utypes as defined in the STC in VOTable note
• STC-X

The transformations should be more or less revertable. Utypes suppress some information embedded in STC that are also defined in VOTables, e.g., units. The extent of STC-X support is about what is given by STC-S, so roundtrips should be possible here.

For inputting STC specifications, STC-S is probably most convenient. We should support all features of STC-S defined in the note, plus

• After flavor, you can add an epoch using something like "Epoch J2000.0".
• After the FK5, FK4 and ECLIPTIC frame specs, you can add an optional astroYear (Bnnnn, Jnnnn) designating a custom equinox.
• There is a system subphrase that lets you specify a system from the STC library (without the ivo:// decoration). It starts with System and is specifed last. It will override all other system specifications.
• You can use identifiers in double quotes whereever values are allowed; this will generate column references.

You can peruse the full grammar understood by this service below; it's machine generated, though, and thus is not terribly readable. So, here are some examples of STC-S expressions:

Position ICRS 12000.3 14000 unit arcsec Error 0.1 0.14
  Resolution 0.5 0.55 Size 1 1.1  4.8 2.3 PixSize 0.2 0.2

Position FK5 J2010 15 16 System TT-ICRS-TOPO

(here, the reference system is ICRS since FK5 J2010 is overridden by the system definition; sorry 'bout mess like this).

Position ICRS "foo" "bar" Error "e_foo" "e_bar"

PositionInterval ICRS Epoch J1900.3 12 13 14 15

PositionInterval ECLIPTIC CART3 12 13 10 14 15 9 PixSize 1 1 1

Circle ICRS Epoch J1999.9 12 13 1 unit arcsec

Convex FK5 J1990 70 190 23 0.125 12 45 30 -0.25

TimeInterval TT 2009-03-10T09:56:10.015625
SpectralInterval 1e10 1e11 unit Hz
RedshiftInterval VELOCITY 1000 7500 unit km/s

Position ICRS Epoch J1999.9
  VelocityInterval Velocity 1 2 unit pc/ha Error 0.25 0.5

Time nil UNKNOWNRefPos MJD302

Difference ICRS Epoch J1999.9 (AllSky Union (Circle 10 10 2
  Intersection (Polygon 10 2 2 10 10 10 Intersection(
    Ellipse 11 11 2 3 30 Not (Difference (
      Circle 12 12 3 Box 11 11 2 3))))))

Redshift BARYCENTER JPL-DE405 3.5

As, promised, here's the full grammar:

_compoundGeoExprBinary ::= "Difference" "(" _compoundGeoOperand _compoundGeoOperand ")"
_compoundGeoExprNary ::= sym0227 "(" _compoundGeoOperand _compoundGeoOperand { _compoundGeoOperand } ")"
_compoundGeoExprUnary ::= "Not" sym0208 _compoundGeoOperand ")"
_compoundGeoExpression ::= sym0213
_compoundGeoOperand ::= sym0210 | _compoundGeoExpression
atomicGeometry ::= sym0189 [ fillfactor ] frame [ refpos ] [ flavor ] [ sym0134 ] { numberLiteral } [ positionSpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0155 ] [ sym0181 ] [ velocityInterval ]
dopplerdef ::= RE<OPTICAL|RADIO|RELATIVISTIC>
eqFrame ::= eqFrameName [ sym0102 ]
eqFrameName ::= "FK5" | "FK4" | "ECLIPTIC"
exactNumericLiteral ::= RE<[+-]?\d+(\.(\d+)?)?|[+-]?\.\d+>
fillfactor ::= "fillfactor" numberLiteral
flavor ::= RE<UNITSPHER|SPHER2|SPHER3|CART3|CART2|CART1>
frame ::= eqFrame | "J2000" | "B1950" | "ICRS" | "GALACTIC" | "GALACTIC_I" | "GALACTIC_II" | "SUPER_GALACTIC" | "GEO_C" | "GEO_D" | "HPR" | "HGS" | "HGC" | "HPC" | "UNKNOWNFrame"
isoTimeLiteral ::= RE<\d\d\d\d-?\d\d-?\d\d(T\d\d:?\d\d:?\d\d(\.\d*)?Z?)?>
jdLiteral ::= "JD" exactNumericLiteral
mjdLiteral ::= "MJD" exactNumericLiteral
numberLiteral ::= RE<(?i)([+-]?\d+(\.(\d+)?)?|[+-]?\.\d+)(E[+-]?\d+)?>
position ::= "Position" frame [ refpos ] [ flavor ] [ sym0134 ] [ { numberLiteral } ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0155 ] [ sym0181 ] [ velocityInterval ]
positionInterval ::= "PositionInterval" [ fillfactor ] frame [ refpos ] [ flavor ] [ sym0134 ] { numberLiteral } [ positionSpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0155 ] [ sym0181 ] [ velocityInterval ]
positionSpec ::= "Position" [ { numberLiteral } ]
redshift ::= "Redshift" [ refpos ] [ redshiftType ] [ dopplerdef ] [ { numberLiteral } ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
redshiftInterval ::= "RedshiftInterval" [ fillfactor ] [ refpos ] [ redshiftType ] [ dopplerdef ] { numberLiteral } [ redshiftSpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
redshiftSpec ::= "Redshift" numberLiteral
redshiftSubPhrase ::= redshiftInterval | redshift
redshiftType ::= RE<VELOCITY|REDSHIFT>
refpos ::= sym0023 [ sym0025 ]
spaceSubPhrase ::= positionInterval | position | atomicGeometry | sym0202 | sym0237 | sym0242
spectral ::= "Spectral" [ refpos ] [ { numberLiteral } ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
spectralInterval ::= "SpectralInterval" [ fillfactor ] [ refpos ] { numberLiteral } [ spectralSpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
spectralSpec ::= "Spectral" numberLiteral
spectralSubPhrase ::= spectralInterval | spectral
startTime ::= "StartTime" [ fillfactor ] [ sym0077 ] [ refpos ] timeLiteral [ sym0039 ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
stcsPhrase ::= [ timeSubPhrase ] [ spaceSubPhrase ] [ spectralSubPhrase ] [ redshiftSubPhrase ] [ systemDefinition ]
stopTime ::= "StopTime" [ fillfactor ] [ sym0077 ] [ refpos ] timeLiteral [ sym0039 ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
sym0023 ::= RE<LOCAL_GROUP_CENTER|GALACTIC_CENTER|UNKNOWNRefPos|EMBARYCENTER|HELIOCENTER|CoordRefPos|RELOCATABLE|BARYCENTER|TOPOCENTER|GEOCENTER|JUPITER|MERCURY|NEPTUNE|URANUS|SATURN|PLUTO|VENUS|LSRD|LSRK|MOON|MARS|LSR>
sym0025 ::= "JPL-DE200" | "JPL-DE405"
sym0039 ::= "Time" timeLiteral
sym0077 ::= RE<UTC|nil|TDB|TT|TEB|LST|TCG|IAT|ET|TCB|TAI|TDT>
sym0102 ::= RE<[BJ][0-9]+([.][0-9]*)?>
sym0134 ::= "Epoch"
sym0155 ::= "Size" numberLiteral { numberLiteral }
sym0181 ::= "PixSize" numberLiteral { numberLiteral }
sym0189 ::= "AllSky" | "Circle" | "Ellipse" | "Box" | "Polygon" | "Convex"
sym0202 ::= "Not" [ fillfactor ] frame [ refpos ] [ flavor ] [ sym0134 ] "(" _compoundGeoOperand ")" [ positionSpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0155 ] [ sym0181 ] [ velocityInterval ]
sym0210 ::= sym0189 { numberLiteral }
sym0213 ::= _compoundGeoExprUnary | _compoundGeoExprBinary | _compoundGeoExprNary
sym0227 ::= "Union" | "Intersection"
sym0237 ::= "Difference" [ fillfactor ] frame [ refpos ] [ flavor ] [ sym0134 ] "(" _compoundGeoOperand _compoundGeoOperand ")" [ positionSpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0155 ] [ sym0181 ] [ velocityInterval ]
sym0242 ::= sym0227 [ fillfactor ] frame [ refpos ] [ flavor ] [ sym0134 ] "(" _compoundGeoOperand _compoundGeoOperand { _compoundGeoOperand } ")" [ positionSpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0155 ] [ sym0181 ] [ velocityInterval ]
sym0266 ::= "Error" numberLiteral { numberLiteral }
sym0303 ::= "Resolution" numberLiteral { numberLiteral }
systemDefinition ::= "System" NOIMPL
time ::= "Time" [ sym0077 ] [ refpos ] [ timeLiteral ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
timeInterval ::= "TimeInterval" [ fillfactor ] [ sym0077 ] [ refpos ] { timeLiteral } [ sym0039 ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
timeLiteral ::= isoTimeLiteral | jdLiteral | mjdLiteral
timeSubPhrase ::= timeInterval | startTime | stopTime | time
timeUnit ::= "unit"
velocityInterval ::= "VelocityInterval" [ fillfactor ] { numberLiteral } [ velocitySpec ] [ timeUnit ] [ sym0266 ] [ sym0303 ] [ sym0181 ]
velocitySpec ::= "Velocity" numberLiteral { numberLiteral }

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