## Changes Introduced in V1.2

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):

1. A new function, astPolyCurveastPolyCurve, has been introduced to allow more efficient plotting of multiple geodesic curves (§21.3).

2. A new set of functions, astResample1#1X2#2astResample1#1X2#2, 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.

3. The command-line options “87#87pgp” and “87#87pgplot”, which were previously synonymous when used with the “ast_linkast_link” and “ast_link_adamast_link_adam” commands, are no longer synonymous. The option “87#87pgp” now causes linking with the Starlink version of PGPLOT (which uses GKS to generate its output), while “87#87pgplot” links with the standard (or “native”) version of PGPLOT.

4. 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.

5. 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.

6. 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.

7. astFindFitsastFindFits now ignores trailing spaces in its keyword template.

8. astPutFitsastPutFits now recognises “D” and “d” as valid exponent characters in floating point numbers.

9. The FitsChan class is now more tolerant of common minor violations of the FITS standard.

10. 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).

11. Some further improvements have been made to the algorithms for simplifying compound Mappings, as used by astSimplifyastSimplify.

12. 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.

13. 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.

14. 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.

15. 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.