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LogTicks(axis) - Space the major tick marks logarithmically?

Description:
This attribute controls the appearance of an annotated coordinate grid (drawn with the astGrid function) by determining whether the major tick marks should be spaced logarithmically or linearly in axis value. It takes a separate value for each physical axis of the Plot so that, for instance, the setting "LogTicks(2)=1" specifies that the major tick marks on the second axis should be spaced logarithmically.

If the LogTicks value for a physical axis is non-zero, the major tick marks on that axis will be spaced logarithmically (that is, there will be a constant ratio between the axis values at adjacent major tick marks). An error will be reported if the dynamic range of the axis (the ratio of the largest to smallest displayed axis value) is less than 10.0. If the LogTicks value is zero, the major tick marks will be evenly spaced (that is, there will be a constant difference between the axis values at adjacent major tick marks). The default is to produce logarithmically spaced tick marks if the corresponding LogPlot attribute is non-zero and the ratio of maximum axis value to minimum axis value is 100 or more. If either of these conditions is not met, the default is to produce linearly spaced tick marks.

Type:
Integer (boolean).
Class Applicability:
Plot
All Plots have this attribute.
Notes:
  • The setting of the LogTicks attribute does not affect the mapping of the plot onto the screen, which is controlled by attribute LogPlot. 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 vica-versa).

  • An error will be reported when drawing an annotated axis grid if the visible part of the physical axis includes the value zero.

  • If no axis is specified, (e.g. "LogTicks" instead of "LogTicks(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 LogTicks(1) value.


next up previous 264
Next: LonAxis - Index of the longitude axis
Up: AST Attribute Descriptions
Previous: LogPlot(axis) - Map the plot logarithmically onto the screen?

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council