catview
is available for browsing catalogues and selecting subsets from the command line. It provides the same
functionality as xcatview
7,
but is much less easy to use. Indeed it is not really intended for casual, interactive usage. If at all
possible I recommend that you use xcatview
for casual, interactive browsing of a catalogue.
However, if you do not have an X display available then you will have to use catview
. It is
also useful for running prepared scripts which perform routine, standard, ‘batch’ type
operations.
In order to run catview
type:
and the following prompt should appear:
Using catview
you can create an arbitrary number of selections from the catalogue, each defined by its
own criteria. catview
has the notion of the ‘current selection’, which is the selection that it is working
on currently. Columns chosen for display to the screen or a text file, are listed from the
current selection and statistics are computed from the current selection. Similarly when a
new selection is created it is extracted from the rows in the current selection. By default
the most recent selection is the current one, though you may choose to make any of the
selections the current one. If no selections have been made, the current selection is the entire
catalogue.
You issue commands to invoke the various functions supported by catview
and reply to the prompts
that they issue, as appropriate. Type HELP
for a list of the commands available. They are as
follows.
OPEN
SHOWCOL
DETCOL
SHOWPAR
DETPAR
SHOWTXT
SHOWROWS
SETCMP
LIST
’ or ‘PREV
’. Both columns in the catalogue and new,
computed columns may be listed. Items in the list should be separated by a semi-colon
(‘;
’). New columns have the form:
where name
is the name of the new column, expression
is the expression which defines it and
units
are the units. name
and expression
are mandatory, but units
is optional. See Appendix A
for the syntax of expressions.
As an example, to list catalogue columns V
, B_V
and a computed column B
defined by ‘V + B_V
’
you would enter:
Occasionally you may need to enter a list of columns and expressions which is longer than a single line. Such long lists can be entered using a continuation line mechanism. This mechanism is described in Section 12.2.
SHOWSEL
CHOSEL
SETSEL
SHOWRNG
SETRNG
3:00:00 | (hours) | |
+45:00:00 | (degrees) | |
0.78539816 | (radians) | |
SETROW
LIST
PREV
SETSTAT
;
’). For example, to compute statistics for columns V
,
B_V
and U_B
you would enter:
Occasionally you may need to enter a list of columns which is longer than a single line. Such long lists can be entered using a continuation line mechanism. This mechanism is described in Section 12.2.
SETDECPL
STATS
none
’
if this option is not required. In either case the statistics will be listed on the display
terminal.
SCOPEN
GRPHDV
TITLE
XEXPR
YEXPR
SCRANGE
SCPLOT
SCSHRNG
SCLOSE
HSOPEN
GRPHDV
TITLE
XEXPR
HSRANGE
HSPLOT
HSSHRNG
HSCLOSE
FILE
0
for the last row number the last row in the selection will be listed (this trick avoids
having to find the number of the last row). The columns specified by SETCMP
are
listed.
SAVECAT
CATOUT
CFLAG
TRUE
FALSE
SETCMP
.
TFLAG
TRUE
FALSE
COMM
SHOWFMT
SETFMT
SETCONF
SWID
SHT
SEQNO
LIST
or PREV
is started with a sequence
number. The options are:
TRUE
FALSE
NLIST
LIST
or PREV
.
ANGRPN
SEXAGESIMAL
RADIANS
ANGRF
TRUE
FALSE
SETFILE
FPGSZE
FWID
FSUMM
A
F
FCOL
A
S
F
FPAR
A
S
F
FTXT
A
F
FTABL
A
S
F
COLNAME
HELP
EXIT
catview
.
In order to run catview
from a script simply type the commands and responses that you would have
issued interactively into a text file. They should be typed exactly as you would enter them
interactively.
Figure 1 shows an example of a script for catview
. It selects quasars with
redshift greater than three and brighter than nineteenth magnitude from a
catalogue8
and writes selected columns from the subset to a file in a format suitable for passing to subsequent
applications (that is, without any annotation). The individual commands are:
OPEN
qsover
’.
SETSEL
SETCMP
ra
, dec
, redshift
, v
.
SETFILE
FILE
qso.lis
.
EXIT
catview
.
OPEN |
qsover |
SETSEL |
Redshift>3.0 .and. v<19.0 |
SETCMP |
ra;dec;redshift;v |
SETFILE |
60 |
132 |
A |
A |
A |
A |
S |
FILE |
1 |
0 |
qso.lis |
EXIT |
To run catview
from a script simply use Unix’s input redirection mechanism:
where catview_script.lis is the name of the script.
Occasionally you might need to enter a long list of columns and expressions for display (catview
option SETCMP
) or a long expression for a selection (catview
option SETSEL
). In both these cases a
continuation line mechanism is available which allows lists and expressions which are longer than a
single input line to be entered. This option is only available in catview
, not in xcatview
. If you need to
specify long lists of columns and expressions to be displayed, or a long expression defining a selection, then you
must use catview
. In practice this restriction is not too onerous because long lines usually arise when
expressions are being used to compute a set of new columns, which is often done from the command
line anyway.
In order to extend the list of columns and expressions to be displayed across several lines simply
append an ‘@
’ character to the end of the line to be continued. The prompt:
will be repeated and the line can be continued. The details are as follows.
@
’ is assumed to be the last.
@
’ used to indicate continuation lines is quite separate from the ‘;
’ used to separate
columns and expressions; ending a line in ‘@
’ does not allow a ‘;
’ to be omitted.
Though this mechanism allows long lists and expressions to be entered, there are necessarily still
limits on the length of the list of columns and expressions for display and on expressions defining
selections, because they are represented within catview
as Fortran 77 CHARACTER variables. In
Version 6.4 of CURSA these limits are:
List of columns and expressions for display: | 1000 characters. |
Expression defining a selection: | 200 characters. |
ra2000
and dec2000
) and sets some existing
columns to be displayed.
ra2000
) being split across several
lines.
Exactly the same syntax applies when entering expressions to define selections.
7Technically xcatview
is a ‘front-end’ tcl/tk graphical user interface which manages the dialogue boxes and forwards
input from the user to the catview
ADAM A-task, which, in turn, manipulates the catalogue. Thus, strictly speaking, you
are running the same application in both cases. However, as a user you will not normally be concerned with these
details.
8The catalogue used in this example is the Catalogue of Quasars and Active Galactic Nuclei by M.-P. Veron-Cetty and P. Veron[29].