$EREF$plot2 module <levels>

This module defines the levels of the contours.

Note: for each contour level, the corresponding
negative level is also calculated and displayed.
$<DL>$
$<DT>${base level} <base_level>$<DD>$
The base level (i.e. the level if there is only one).
Each data set can individually scale this if desired.

$<DT>${number of levels} <number_of_levels>$<DD>$
The number of contour levels.

$<DT>${change between levels} <change_between_levels>$<DD>$
The change between each level (if there is more than one).

$<DT>${multiplicative : additive } <change_mode>$<DD>$
This determines whether each of the levels is obtained by
adding or multiplying by the change between levels.

$<DT>${base level modifier} <level_modifier>$<DD>$
In conjunction with the next four buttons, this allows a
quick change of the base level (i.e. without typing).

$<DT>${* : / : + : -} <multiply> <divide> <add> <subtract>$<DD>$
This carries out the indicated operation on the base level
using the base level modifier, then calculates the contours
and displays the result.

$<DT>${timer on : timer off } <timer_mode>$<DD>$
This determines whether the timer is on (visible) while
the contours are being calculated and drawn.

$<DT>${apply} <apply>$<DD>$
Calculate the contours and display the result.
The current parameters (e.g. the region and contour
levels) as defined are the ones used.

$<DT>${dismiss}$<DD>$
Close the module (the parameters are remembered).

$<DT>${help}$<DD>$
Display this message.
$</DL>$
