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Last modified: December 2013

URL: http://cxc.harvard.edu/chips/ahelp/log_scale.html
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AHELP for CIAO 4.9 ChIPS v1

log_scale

Context: axes

Synopsis

Changes the plot axis to use a logarithmic scale.

Syntax

log_scale()
log_scale(dimension)
log_scale(plotname)
log_scale(plotname, dimension)
log_scale(id)
log_scale(id, dimension)

The function is also available as logarithmic_scale().

Description

The function arguments.

Argument Description
dimension One of X_AXIS, Y_AXIS, or XY_AXIS to specify the X axis, Y axis, or both.
plotname The name of the plot to modify, as a string.
id A ChipsId structure identifying the item.

The log_scale command changes the given axis (or axes) to use a logarithmic scale. To change back to a linear scale use the lin_scale command.

When the scale of an axis is changed, any axes that are bound to that axis are also changed, including plot border axes; see the bind_axes command for more information.

How negative values are handled

If the lower limit of an axis is 0 or less, then the lower limit will be re-calculated from the smallest positive value in the associated data set(s) for that axis. This happens whether the axis limit is "AUTO" or has been set to a specific value.

If both limits are 0 or less then the call will succeed but the axis will display no data or tick marks.

Example 1

chips> log_scale()

Set the current X and Y axis to log scale.

Example 2

chips> log_scale(X_AXIS)

Set the current X axis to log scale.

Example 3

chips> log_scale("plot1")

These commands change the X and Y axes of the plot called "plot1" to a logarithmic scale.

Example 4

chips> id = ChipsId()
chips> id.plot = "plot1"
chips> log_scale(id)

An alternative means to change the scaling of the axes in plot "plot1". This method is the only way to directly change a plot that is not in the current frame: for example

chips> id.window = "win2"
chips> id.plot = "plot2"
chips> log_scale(id, Y_AXIS)

will change the Y axis of the plot called "plot2" in window "win2" to be drawn with a logarithmic scale.

Bugs

See the bugs pages on the ChIPS website for an up-to-date listing of known bugs.

See Also

axes
add_axis, bind_axes, current_axis, delete_axis, display_axis, display_major_ticks, display_minor_ticks, get_axis, get_xaxis, get_yaxis, hide_axis, hide_major_ticks, hide_minor_ticks, lin_scale, move_axis, reverse_axes, set_arbitrary_tick_positions, set_axis, set_xaxis, set_yaxis, shuffle_axis, unbind_axes
concepts
preferences
contrib
chips_utils
limits
get_plot_range, limits, panto, pick_limits, zoom
plots
add_plot, adjust_grid_gaps, adjust_grid_xrelsize, adjust_grid_xrelsizes, adjust_grid_yrelsize, adjust_grid_yrelsizes, clear_plot, current_plot, delete_plot, display_plot, get_plot, grid_objects, hide_plot, move_plot, reposition_plot, set_data_aspect_ratio, set_plot, set_plot_aspect_ratio, split, strip_chart, swap_object_positions
preference
get_preference, get_preferences, load_preferences, save_preferences, set_preference, set_preference_autoload, set_preferences

Last modified: December 2013
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