### CURSE

Use the cursor to get interactive input

#### Description:

Display the cursor and perform various interactive tasks. These tasks are as follows:
• Q – QUIT The application ends.

• D – DRAW A line is drawn from the PGPLOT "current position" to the cursor position. This position is also written to the internal label list.

• E – EXPAND The plotting limits are expanded by a factor of 2 about the position of the cursor. No other action is taken. This allows the screen to be cleared and the graph to be re-plotted without having to set the limits explicitly.

• G – GRADIENT Draw a line between two consecutive cursor hits and report the gradient of the line.

• L – LABEL Write a label directly onto the plot. The application uses up to two points which define the angle at which the label is to be drawn. Once "L" has been pressed, you are given the option to add another point in the standard PGPLOT fashion (c.f. the PGPLOT routine PGNCURSE); i.e. :

• A – add a point

• D – delete a point

• X – finish

On pressing the "X" key, a label is prompted for. If only one point is supplied, the label is plotted horizontally.
• M – MARK Mark the current cursor position with the current symbol type.

• O – ANNOTATE The label for the nearest data point is written with its right hand end at the position defined by the cursor. The information to create this label is stored in an internal table. This information can be written out into file suitable for including in an ICL command file by using the WRITEI application, e.g. :

PONGO$>$ WRITEI LABLST

• P – ANNOTATE The label for the nearest data point is written with its left hand end at the position defined by the cursor. The information to create this label is stored in an internal table. This information can be written out into file suitable for including in an ICL command file by using the WRITEI application, e.g. :

PONGO$>$ WRITEI LABLST

• S – SHRINK The plotting limits are set so as to zoom out by a factor of 2 about the position of the cursor. No other action is taken. This allows the screen to be cleared and the graph to be re-plotted without having to set the limits explicitly.

• V – MOVE The PGPLOT "current position" will be set to the cursor position. This position is also written to the internal label list.

• X – POSITION The current position of the cursor in world coordinates is written to the terminal and the XCURSE and YCURSE parameters.

• Z – ZOOM The limits for a zoomed version of the current plot are set. The application will prompt for two points which define the bottom left corner and the top right corner of the new graph surface.

• A – add a point

• D – delete a point

• X – finish

#### Usage:

curse [symbol] label=?

#### Parameters:

The symbol number used in the MARK option.

If the value is not specified on the command line, the current value is used. The current value is initially set to 1.

The label to be written to the screen with the LABEL option.

[The value is prompted for.]

##### JUSTIFICATION = _REAL (Read and Write)
The justification about the point (in the range 0.0 to 1.0). Here, 0.0 means left justify the text relative to the data point, 1.0 means right justify the text relative to the data point, 0.5 means centre the string on the data point, other values will give intermediate justifications.

If the value is not specified on the command line, the current value is used. The current value is initially set to 0.5 (i.e. centre the text).

##### XCURSE = _REAL (Write)
The X-axis position of the last graphics cursor hit when using the "X" option.

The value is written to the PONGO_XCURSE global parameter.

##### YCURSE = _REAL (Write)
The Y-axis position of the last graphics cursor hit when using the "X" option.

The value is written to the PONGO_YCURSE global parameter.

##### XMIN = _REAL (Write)
The left hand edge of the world coordinate limits. The value is set by the application in the zooming options. It is not intended that the value be specified on the command line.

The value is written to the global parameter PONGO_XMIN.

##### XMAX = _REAL (Write)
The right hand edge of the world coordinate limits. The value is set by the application in the zooming options. It is not intended that the value be specified on the command line.

The value is written to the global parameter PONGO_XMAX.

##### YMIN = _REAL (Write)
The lower edge of the world coordinate limits. The value is set by the application in the zooming options. It is not intended that the value be specified on the command line.

The value is written to the global parameter PONGO_YMIN.

##### YMAX = _REAL (Write)
The upper edge of the world coordinate limits. The value is set by the application in the zooming options. It is not intended that the value be specified on the command line.

The value is written to the global parameter PONGO_YMAX.

The projection that has been used to plot the data. This is explained in more detail in the section on projections. Allowed values: "NONE", "TAN", "SIN", "ARC", "GLS", "AITOFF", "MERCATOR" and "STG".

This parameter is not specified on the command line. The value of the global parameter PONGO_PROJECTN is used. If PONGO_PROJECTN is not defined, the default value "NONE" is used.

The centre of the projection in RA (i.e. the angle must be specified as hh:mm:ss.sss). This parameter is only required for PROJECTION values other than "NONE".

This parameter is not specified on the command line. The value of the global parameter PONGO_RACENTRE is used. If PONGO_RACENTRE is not defined, the default value "0" is used.

The centre of the projection in declination (i.e. the angle must be specified as dd:mm:ss.sss). This parameter is only required for PROJECTION values other than "NONE".
This parameter is not specified on the command line. The value of the global parameter PONGO_DECCENTRE is used. If PONGO_DECCENTRE is not defined, the default value "0" is used.