Chandra X-Ray Observatory
Skip to the navigation links
Last modified: 14 December 2016

How do I change the appearance/location of the axis labels?

Note: the axis label refers to the (normally) textual label offset from the axis; the (normally) numeric labels drawn at major tick marks are referred to as "ticklabels" in ChIPS.

The set_axis, set_xaxis and set_yaxis commands are used to change the appearance of the axis label. In the example below we use set_axis to change the color, size, and font of both axis labels:

chips> set_axis(["label.font", "times", "label.color", "green", "label.size", 18])

The get_xaxis and get_yaxis commands can be used to find the current settings: here we show the Y axis values after the above command has been called:

chips> get_yaxis().label

color = green
font = times
fontstyle = normal
halign = 0.5
size = 18
valign = 0.0
visible = True
chips> get_yaxis().y

label.angle = 90.0
label.text = 
stem = None

The halign, valign, and angle attributes above control the position of the label with respect to a control point; this control point is determined by the offset.perpendicular and offset.parallel settings of an axis:

chips> get_yaxis().offset

parallel = 0.0
perpendicular = 40.0

The units are pixels, so to move a label further away from an axis (whether X or Y), increase the offset.perpendicular setting; for instance

chips> set_yaxis(["offset.perpendicular", 60])

Axes and borders

The borders around a plot - which can be displayed or hidden by changing the style attribute of the plot - will reflect the major properties of the plot axes (e.g. limits and scaling); they act like bound axes. For those properties that are not synchronised with the plot axes, the set_axis command can be used, either with the specific name of the border (reported by the info command), or by using the label "all":

chips> set_axis('by2', ['minortick.visible', False])
chips> set_axis('all', ['', 'outside', '', 'outside'])


The ChIPS GUI makes it easy to modify a visualization using your mouse, rather than Python functions. The GUI can also be used to add annotations - such as labels, lines, points and regions - and to zoom or pan into plots.

Last modified: 14 December 2016
Smithsonian Institute Smithsonian Institute

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email: Smithsonian Institution, Copyright © 1998-2017. All rights reserved.