As a broad outline, applications use the CTG_ package as follows:
This is a complicated example, probably more complicated than would be used in practice,
but it highlights the facilities of the GRP and CTG packages, e.g. wild cards (“?
”,
“”
or “
[..]
” ), lists of files, or indirection through a text file (“
”). The braces indicate the second
FITS extension.
^
The CTG_ASSOC routine produces a list of explicit catalogue names, which are stored internally within the GRP system.
The routine CTG_CREAT produces a group containing the names of catalogues that are to be created by the application. The routine CTG_CATCR will create a new catalogue with a name given by a group member, and returns a CAT identifier to it.
The names of output catalogues given by users usually relate to the input catalogue names. When CTG_CREAT is called, it creates a group of catalogue names either by modifying all the names in a specified input group using a modification element (see SUN/150), or by getting a list of new names from the user.
See the detailed descriptions of CTG_ASSOC and CTG_CREAT below for details of the processing of existing and new catalogue names.