General Changes

• Graphics applications are now linked with native PGPLOT , instead of the Starlink GKS-based version of PGPLOT . Graphics device names can be given either in the native
  PGPLOT style (e.g. "/CPS" for landscape colour encapsulated PostScript) or in the equivalent traditional Starlink style (e.g. "epsfcol_l"). Note, PostScript output is now written to a file called pgplot.ps by default, and each graphics command will overwrite any existing file with this name. That is, no sequence number is added to the end of the file name as used to be the case with the GKS version of PGPLOT . In order to avoid over-writing previous graphics files, you can specify an alternative output file to use when giving the device name, as in the following examples; fred.ps/CPS or epsfcol_l;fred.ps.

• The distinction getween graphics devices and image displays has been removed. All graphics output from all commands now goes to the current graphics device set with GDSET. The ID... commands have been removed.

• Support for overlay devices has been removed since there are no native PGPLOT drivers for them. The OV... Commands have been removed.

• Colours can now be specified as RGB intensity triplets, or as HTML colour codes, in addition to the previous forms.

• The appearance of textual labels, numerical labels, tick marks, and axes can now be specified independently for the two axes of a plot. See here.

• Each picture in the graphics database now has a co-ordinate Frame  with Domain ``NDC'' associated with it. This Frame covers the whole graphics device is (0, 0) at the bottom-left corner and (1, 1) at the top-right corner. The name ``NDC'' can now be used with applications such as GDSTATE.

• Applications which read positions lists from catalogue files can now read lists from catalogues which do not contain a WCS FrameSet. If no WCS FrameSet is found, then a search is made for columns called ``RA'' and ``DEC''. If these columns are found, they are used (is possible), and qualified by any EPOCH and EQUINOX parameters in the catalogue. If no such columns are found, a search is made for columns called ``X'' and ``Y''. If found, they are assumed to hold positions in the GRID co-ordinate Frame. GRID co-ordinates are like PIXEL co-ordinates except the centre of the bottom-left pixel always has GRID co-ordinates ( 1.0, 1.0 ). If a ``Z'' column also exists, the GRID co-ordinates are assumed to be three-dimensional.

• Applications which create catalogues holding positions lists now allow the user to specify the co-ordinate Frame in which positions should be stored within the catalogue columns. This is done using a new parameter called CATFRAME which has been added to all appropriate commands. Previously positions were always stored in the base Frame of the associated WCS information. Now, the default is to use SKY co-ordinates if available, otherwise PIXEL co-ordinates.