The following describes the most significant changes which occurred in
the AST library between versions V1.1 and V1.2 (not the most recent
version):
- A new function, astPolyCurveastPolyCurve, has been introduced to allow more
efficient plotting of multiple geodesic curves
(§21.3).
- A new set of functions, astResample
X
astResample
X
, has been introduced
to perform resampling of gridded data such as images
(i.e. re-gridding) under the control of a geometrical
transformation specified by a MappingMapping.
- The command-line options “
pgp” and “
pgplot”, which
were previously synonymous when used with the “ast_linkast_link” and
“ast_link_adamast_link_adam” commands, are no longer synonymous. The option
“
pgp” now causes linking with the Starlink version of PGPLOT
(which uses GKS to generate its output), while “
pgplot” links
with the standard (or “native”) version of PGPLOT.
- The function astMapBoxastMapBox has been changed to execute more quickly,
although this has been achieved at the cost of some loss of robustness
when used with difficult Mappings.
- A new value of “FITS-IRAF” has been introduced for the
EncodingEncoding attribute of a FitsChanFitsChan. This new encoding provides an
interim solution to the problem of storing coordinate system
information in FITS headers, until the proposed new FITS-WCS standard
becomes stable.
- When a FrameSetFrameSet is created from a set of FITS header cards (by
reading from a FitsChan using a “foreign” encoding), the base FrameFrame
of the resulting FrameSet now has its DomainDomain attribute set to
“GRID”. This reflects the fact that this Frame represents FITS data
grid coordinates (equivalent to FITS pixel coordinates—see
§7.13). Previously, this Domain value was not
set.
- astFindFitsastFindFits now ignores trailing spaces in its keyword template.
- astPutFitsastPutFits now recognises “D” and “d” as valid exponent
characters in floating point numbers.
- The FitsChan class is now more tolerant of common minor
violations of the FITS standard.
- The FitsChan class now incorporates an improved test for the
linearity of Mappings, allowing more reliable conversion of AST data
into FITS (using “foreign” FITS encodings).
- Some further improvements have been made to the algorithms for
simplifying compound Mappings, as used by astSimplifyastSimplify.
- A new UnitRadiusUnitRadius attribute has been added to the SphMapSphMap
class. This allows improved simplification of compound Mappings
(CmpMaps) involving SphMaps and typically improves performance when
handling FITS world coordinate information.
- A MatrixMapMatrixMap no longer propagates input coordinate values of
AST__BAD automatically to all output coordinates. If certain output
coordinates do not depend on the affected input coordinate(s) because
the relevant matrix elements are zero, then they may now remain valid.
- A minor bug has been corrected which could cause certain
projections which involve half the celestial sphere to produce valid
coordinates for the other (unprojected) half of the sphere as well.
- A bug has been fixed which could occasionally cause astConvertastConvert
to think that conversion between a CmpFrameCmpFrame and another Frame was
possible when, in fact, it wasn't.