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java.lang.Object uk.ac.starlink.ast.AstObject uk.ac.starlink.ast.Mapping uk.ac.starlink.ast.SlaMap
public class SlaMap
Java interface to the AST SlaMap class  sequence of celestial coordinate conversions. An SlaMap is a specialised form of Mapping which can be used to represent a sequence of conversions between standard celestial (longitude, latitude) coordinate systems.
When an SlaMap is first created, it simply performs a unit (null) Mapping on a pair of coordinates. Using the astSlaAdd function, a series of coordinate conversion steps may then be added, selected from those provided by the SLALIB Positional Astronomy Library (Starlink User Note SUN/67). This allows multistep conversions between a variety of celestial coordinate systems to be assembled out of the building blocks provided by SLALIB.
For details of the individual coordinate conversions available, see the description of the astSlaAdd function.
This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public Licence for more details.
You should have received a copy of the GNU General Public Licence along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street,Fifth Floor, Boston, MA 021101301, USA
Nested Class Summary 

Nested classes/interfaces inherited from class uk.ac.starlink.ast.Mapping 

Mapping.Interpolator, Mapping.Spreader 
Field Summary 

Fields inherited from class uk.ac.starlink.ast.Mapping 

LINEAR_INTERPOLATOR, LINEAR_SPREADER, NEAREST_INTERPOLATOR, NEAREST_SPREADER 
Fields inherited from class uk.ac.starlink.ast.AstObject 

AST__BAD, AST__TUNULL, pointer 
Constructor Summary  

SlaMap()
Creates a default SlaMap. 

SlaMap(int flags)
Creates a SlaMap. 
Method Summary  

void 
add(String cvt,
double[] args)
Add a celestial coordinate conversion to an SlaMap. 
Methods inherited from class uk.ac.starlink.ast.Mapping 

decompose, getInvert, getNin, getNout, getReport, getTranForward, getTranInverse, invert, linearApprox, mapBox, mapSplit, rate, rebin, rebinD, rebinF, rebinI, resample, resampleB, resampleD, resampleF, resampleI, resampleL, resampleS, setInvert, setReport, simplify, tran1, tran2, tranGrid, tranN, tranP 
Methods inherited from class uk.ac.starlink.ast.AstObject 

annul, clear, copy, delete, equals, finalize, getAstConstantI, getB, getC, getD, getF, getI, getID, getIdent, getL, getNobject, getObjSize, getRefCount, hashCode, isThreaded, reportVersions, sameObject, set, setB, setC, setD, setF, setI, setID, setIdent, setL, show, test, tune 
Methods inherited from class java.lang.Object 

clone, getClass, notify, notifyAll, toString, wait, wait, wait 
Constructor Detail 

public SlaMap()
public SlaMap(int flags)
flags
 This parameter is reserved for future use and should currently
always be set to zero.
AstException
 if an error occurred in the AST libraryMethod Detail 

public void add(String cvt, double[] args)
When an SlaMap is first created (using astSlaMap), it simply performs a unit (null) Mapping. By using astSlaAdd (repeatedly if necessary), one or more coordinate conversion steps may then be added, which the SlaMap will perform in sequence. This allows multistep conversions between a variety of celestial coordinate systems to be assembled out of the building blocks provided by SLALIB.
Normally, if an SlaMap's Invert attribute is zero (the default), then its forward transformation is performed by carrying out each of the individual coordinate conversions specified by astSlaAdd in the order given (i.e. with the most recently added conversion applied last).
This order is reversed if the SlaMap's Invert attribute is nonzero (or if the inverse transformation is requested by any other means) and each individual coordinate conversion is also replaced by its own inverse. This process inverts the overall effect of the SlaMap. In this case, the first conversion to be applied would be the inverse of the one most recently added.
 "ADDET" (EQ): Add Eterms of aberration.
 "SUBET" (EQ): Subtract Eterms of aberration.
 "PREBN" (BEP0,BEP1): Apply BesselNewcomb preIAU 1976 (FK4)
precession model.
 "PREC" (EP0,EP1): Apply IAU 1975 (FK5) precession model.
 "FK45Z" (BEPOCH): Convert FK4 to FK5 (no proper motion or parallax).
 "FK54Z" (BEPOCH): Convert FK5 to FK4 (no proper motion or parallax).
 "AMP" (DATE,EQ): Convert geocentric apparent to mean place.
 "MAP" (EQ,DATE): Convert mean place to geocentric apparent.
 "ECLEQ" (DATE): Convert ecliptic coordinates to FK5 J2000.0 equatorial.
 "EQECL" (DATE): Convert equatorial FK5 J2000.0 to ecliptic coordinates.
 "GALEQ": Convert galactic coordinates to FK5 J2000.0 equatorial.
 "EQGAL": Convert FK5 J2000.0 equatorial to galactic coordinates.
 "HFK5Z" (JEPOCH): Convert ICRS coordinates to FK5 J2000.0 equatorial.
 "FK5HZ" (JEPOCH): Convert FK5 J2000.0 equatorial coordinates to ICRS.
 "GALSUP": Convert galactic to supergalactic coordinates.
 "SUPGAL": Convert supergalactic coordinates to galactic.
 "J2000H": Convert dynamical J2000.0 to ICRS.
 "HJ2000": Convert ICRS to dynamical J2000.0.
 "R2H" (LAST): Convert RA to Hour Angle.
 "H2R" (LAST): Convert Hour Angle to RA.
For example, to use the "ADDET" conversion, which takes a single argument EQ, you should consult the documentation for the SLALIB routine SLA_ADDET. This describes the conversion in detail and shows that EQ is the Besselian epoch of the mean equator and equinox. This value should then be supplied to astSlaAdd in args[0].
In addition the following strings may be supplied for more complex conversions which do not correspond to any one single SLALIB routine (DIURAB is the magnitude of the diurnal aberration vector in units of "day/(2.PI)", DATE is the Modified Julian Date of the observation, and (OBSX,OBSY,OBZ) are the HeliocentricAriesEcliptic cartesian coordinates, in metres, of the observer):
 "HPCEQ" (DATE,OBSX,OBSY,OBSZ): Convert HelioprojectiveCartesian coordinates to J2000.0 equatorial.
 "EQHPC" (DATE,OBSX,OBSY,OBSZ): Convert J2000.0 equatorial coordinates to HelioprojectiveCartesian.
 "HPREQ" (DATE,OBSX,OBSY,OBSZ): Convert HelioprojectiveRadial coordinates to J2000.0 equatorial.
 "EQHPR" (DATE,OBSX,OBSY,OBSZ): Convert J2000.0 equatorial coordinates to HelioprojectiveRadial.
 "HEEQ" (DATE): Convert helioecliptic coordinates to J2000.0 equatorial.
 "EQHE" (DATE): Convert J2000.0 equatorial coordinates to helioecliptic.
 "H2E" (LAT,DIRUAB): Convert horizon coordinates to equatorial.
 "E2H" (LAT,DIURAB): Convert equatorial coordinates to horizon.
Note, the "H2E" and "E2H" conversions convert between topocentric horizon coordinates (azimuth,elevation), and apparent local equatorial coordinates (hour angle,declination). Thus, the effects of diurnal aberration are taken into account in the conversions but the effects of atmospheric refraction are not.
cvt
 Pointer to a nullterminated string which identifies the
celestial coordinate conversion to be added to the
SlaMap. See the "SLALIB Conversions" section for details of
those available.args
 An array containing argument values for the celestial
coordinate conversion. The number of arguments required, and
hence the number of array elements used, depends on the
conversion specified (see the "SLALIB Conversions"
section). This array is ignored
and a NULL pointer may be supplied
if no arguments are needed.
AstException
 if an error occurred in the AST library


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