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LogPlot(axis) - Map the plot logarithmically onto the screen?

Description:
This attribute controls the appearance of all graphics produced by the Plot, by determining whether the axes of the plotting surface are mapped logarithmically or linearly onto the base Frame of the FrameSet supplied when the Plot was constructed. It takes a separate value for each axis of the graphics coordinate system (i.e. the base Frame in the Plot) so that, for instance, the setting "LogPlot(2)=1" specifies that the second axis of the graphics coordinate system (usually the vertical axis) should be mapped logarithmically onto the second axis of the base Frame of the FrameSet supplied when the Plot was constructed.

If the LogPlot value of a Plot axis is non-zero, it causes that axis to be mapped logarithmically, otherwise (the default) the axis is mapped linearly.

Type:
Integer (boolean).
Class Applicability:
Plot
All Plots have this attribute.
Notes:
  • The setting of the LogPlot attribute provides the default value for the related LogTicks attribute. By selecting suitable values for LogPlot and LogTicks, it is possible to have tick marks which are evenly spaced in value but which are mapped logarithmically onto the screen (and vice-versa).

  • An axis may only be mapped logarithmically if the visible part of the axis does not include the value zero. The visible part of the axis is that part which is mapped onto the plotting area, and is measured within the base Frame of the FrameSet which was supplied when the Plot was constructed. Any attempt to set LogPlot to a non-zero value will be ignored (without error) if the visible part of the axis includes the value zero

  • If no axis is specified, (e.g. "LogPlot" instead of "LogPlot(2)"), then a "set" or "clear" operation will affect the attribute value of all the Plot axes, while a "get" or "test" operation will use just the LogPlot(1) value.


next up previous 264
Next: LogTicks(axis) - Space the major tick marks logarithmically?
Up: AST Attribute Descriptions
Previous: LogLabel(axis) - Use exponential format for numerical axis labels?

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council