Browsing and selecting from the command line

catview is available for browsing catalogues and selecting subsets from the command line. It provides the same functionality as xcatview⁷, 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:

catview

and the following prompt should appear:

ACTION - Action: /''/ $>$

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

Open a catalogue. You will be prompted for the name of the catalogue.

SHOWCOL

List a summary of all the columns in the catalogue.

DETCOL

List full details of all the columns in the catalogue.

SHOWPAR

List a summary of all the parameters in the catalogue.

DETPAR

List full details of all the parameters in the catalogue.

SHOWTXT

List the textual information associated with the catalogue.

SHOWROWS

Display the number of rows in the current selection.

SETCMP

Enter the list of columns which are to be displayed. The list defines the columns which are listed by commands `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:

name{expression}units

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  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:

V;B_V;B{V+B_V}

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 .

SHOWSEL

List details of all the selections which currently exist.

CHOSEL

Choose one of the existing selections to become the current selection.

SETSEL

Create a new selection. You will be prompted to enter the expression defining the selection (see Appendix ). Occasionally you may need to enter an expression which is longer than a single line. Such long expressions can be entered using a continuation line mechanism. This mechanism is described in Section .

SHOWRNG

List the columns on which a (fast) range selection can be created; that is, the columns on which the catalogue is sorted. In practice the catalogue is unlikely to be simultaneously sorted on more than one column.

SETRNG

Create a new range selection. Range selections can be created essentially instantaneously, irrespective of the size of the catalogue. However they can only be created on sorted columns. You will be prompted for the name of the required column and the minimum and maximum values to be included in the range. If the column contains a celestial coordinate in a format that CURSA can recognise (see Appendix ) then the minimum and maximum values can optionally be entered as sexagesimal values in hours or degrees. The usual rules for interpreting sexagesimal values in expressions are followed. For example any of the following three values could be entered and all correspond to the same coordinate:

3:00:00		(hours)
+45:00:00		(degrees)
0.78539816		(radians)

SETROW

Set the current row number. You will be prompted to supply the required row number.

LIST

List the next page of output to the display terminal.

PREV

List the previous page of output to the display terminal.

SETSTAT

Enter the list of columns for which statistics are to be computed. The list should comprise column names separated be semi-colons (`;'). For example, to compute statistics for columns V, B_V and U_B you would enter:

V;B_V;U_B

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 .

SETDECPL

Set the number of decimal places to which the statistics will be displayed; you will be prompted to enter the required number. Note that this option merely controls the number of decimal places to which the statistics are displayed. They are always computed as DOUBLE PRECISION numbers in order to ensure the maximum possible accuracy.

STATS

Compute statistics for the specified columns from the current selection. Optionally the statistics can be saved as a text file. You will be prompted for the required file name; enter `none' if this option is not required. In either case the statistics will be listed on the display terminal.

SCOPEN

Open a new scatter-plot. You will be prompted for the following information.

GRPHDV

The name of the graphics device on which the plot will be drawn. See Section  and Table  for details of the graphics devices available.

TITLE

The title of the plot.

XEXPR

The column or expression to be plotted as the $x$ axis.

YEXPR

The column or expression to be plotted as the $y$ axis.

SCRANGE

Set the axis ranges of a scatter-plot. You will be prompted to indicate whether the plot is to be auto-scaled and also the axis ranges required. Note that the ranges are prompted for (but not used) even if the plot is to be auto-scaled.

SCPLOT

Plot a scatter-plot from the current selection. You will be prompted for the plotting symbol and symbol colour required.

SCSHRNG

Show the range of the current scatter-plot.

SCLOSE

Close the current scatter-plot.

HSOPEN

Open a new histogram. You will be prompted for the following information.

GRPHDV

The name of the graphics device on which the plot will be drawn. See Section  and Table  for details of the graphics devices available.

TITLE

The title of the plot.

XEXPR

The column or expression to be plotted as the $x$ axis.

HSRANGE

Set the $x$ axis range and other details of a histogram. You will be prompted to indicate whether the histogram is to be auto-scaled and also the $x$ axis range required. Note that the range is prompted for (but not used) even if the plot is to be auto-scaled. Other details required are the specification for each histogram bin (the total number of bins or the width of each bin) and whether the histogram is to be normalised.

HSPLOT

Plot a histogram from the current selection. You will be prompted for the line colour required.

HSSHRNG

Show the range of the current histogram.

HSCLOSE

Close the current histogram.

FILE

List the current selection to a text file. You will be prompted for the first and last rows (within the current selection) to be listed and for the output file name. If you enter 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

Save the current selection as a catalogue. You will be prompted for the following information.

CATOUT

The name of the new catalogue.

CFLAG

The set of columns to be included in the new catalogue. The possible replies are:

TRUE

include all the columns in the original catalogue,

FALSE

include only the columns currently specified by SETCMP.

TFLAG

Specify whether or not to copy the textual information associated with the original catalogue to the new catalogue. The possible replies are:

TRUE

copy the textual information,

FALSE

do not copy the textual information.

COMM

Enter a line of text to be added as comments to the new catalogue.

SHOWFMT

Show the data type, units and external display format for a column. You will be prompted for the name of the required column.

SETFMT

Set a new external display format and units for a given column. You will be prompted for the name of the column and the new external display format and units. Remember that the external display format must be a valid Fortran 77 format for the data type of the column.

SETCONF

Set a number of screen configuration options. You will be prompted to supply the following options.

SWID

The screen height in characters.

SHT

The screen width in characters.

SEQNO

Specify whether each line listed by LIST or PREV is started with a sequence number. The options are:

TRUE

include a sequence number,

FALSE

do not include a sequence number.

NLIST

The number of lines to be output by a single invocation of LIST or PREV.

ANGRPN

Specify the way in which columns recognised by CURSA as containing angles (see Section  and Appendix ) are to be listed. The options are:

SEXAGESIMAL

output as sexagesimal hours or degrees,

RADIANS

output as radians.

ANGRF

Specify whether UNITS attribute of angles is to be reformatted prior to display. The options are:

TRUE

reformat the UNITS attribute,

FALSE

do not reformat the UNITS attribute.

SETFILE

Set a number of configuration options for the output text file. Most of these options define the items which will be included in the text file. You will be prompted to supply the following options.

FPGSZE

The number of lines in each page of the output file.

FWID

The width of each line of the output file in characters.

FSUMM

Specify whether a summary of the catalogue is to be included. The options are:

A

do not include a summary,

F

include a summary.

FCOL

Specify whether details of all the columns are to be included. The options are:

A

do not include any details,

S

include a summary,

F

include full details.

FPAR

Specify whether details of all the parameters are to be included. The options are:

A

do not include any details,

S

include a summary,

F

include full details.

FTXT

Specify whether a copy of the textual information is to be included. The options are:

A

do not include the textual information,

F

include the textual information.

FTABL

Specify whether a table of values is to be included. The options are:

A

do not include the table,

S

include the table, but without any column headings,

F

include the table with column headings.

COLNAME

List the names of all the columns in the catalogue.

HELP

Display a brief list of all the commands available.

EXIT

Terminate catview.