Selecting subsets from a catalogue

Subsets can be extracted from a catalogue according to some criteria using either the catalogue browsers xcatview (see Section ) and catview (see Section ) or using application catselect. Whereas the selection options in the catalogue browsers are oriented towards the interactive exploration and display of catalogues, catselect is oriented towards creating `one-off' selections from a catalogue and saving them as a new catalogue. Also, catselect contains options for types of selections which are not available in the catalogue browsers.

The remainder of this section describes catselect. In addition to saving the selected objects as a new catalogue, catselect provides an option to save the rejected objects, which did not meet whatever criteria was specified, to a second catalogue. The types of selection available in catselect are listed in Table  and described in Section .

Table: Types of selection available in catselect

Type of selection	Option	Browser?
Arbitrary expression	E	$\bullet$
Range within a sorted column	R	$\bullet$
Rows inside a rectangle	A	($\bullet$)
Rows inside a circle	C	($\bullet$)
Rows inside a polygon	P
Every $n$th row	N

The `Option' column lists the response to prompt SETYP which corresponds to the type of selection.

The `Browser?' column indicates whether the type of selection is available in the catalogue browsers xcatview and catview. A bullet (`$\bullet$') indicates that the type of selection is available. A bullet in parenthesis (`($\bullet$)') indicates that the type of selection is available in the browsers by entering the appropriate arbitrary expression.