The Aux Axis control () is only visible
when at least one layer is using the shared colour map.
The following plot layers do this:
If no layer is using the shared colour map, then this control will not appear in the stack.
When present, this control has three following tabs.
Aux axis control Map tab
The Map tab controls the aux axis colour map. It has the following options:
The default range is clipped at one end for colour maps that fade to white, so that all the plotted colours will be distinguisable against a white background. That is generally a good idea for scatter-type plots, but may not be so good for plots where the whole plotting surface is coloured in, like density maps or spectrograms, so in that case you might want to uncheck Default and leave the handles at the extreme ends of the slider.
linear
log
histogram
histolog
square
sqrt
linear
, log
, square
and
sqrt
options just apply the named function to the
full data range.
The histogram options on the other hand use a scaling function
that corresponds to the actual distribution of the data, so that
there are about the same number of points (or pixels, or whatever
is being scaled) of each colour.
The histogram options are somewhat more expensive,
but can be a good choice if you are exploring data whose
distribution is unknown or not well-behaved over its min-max range.
The histogram
and histolog
options both
assign the colours in the same way, but they display the colour
ramp with linear or logarithmic annotation respectively;
the histolog
option also ignores non-positive values.
Aux axis control Ramp tab
The Ramp tab controls the display and annotation of the colour ramp that displays the colour map on the plot. It has the following options:
Aux axis control Range tab
The Range tab lets you enter lower and upper values for the aux data range by hand, and provides a double slider to restrict the range within these limits. If either the lower or upper range is left blank, it will be determined from the data.
The Lock Aux Range checkbox controls whether
the aux range is automatically updated as the plot is adjusted
(for instance as you navigate around it with the mouse).
If locked, the range will stay the same, but otherwise (the default)
it is dynamically updated for the current view of the plot.
This checkbox is a duplicate of the toggle button on the plot
window toolbar described in Appendix A.4.2.
Note the font used for labelling the aux axis is currently controlled by the font from the Axes selector.