Log Scale

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Log Scale

It is also possible to plot the data on a log scale. To do this, type

Use LOg X to use a log scale on the x-axis. The LOg OFf command will turn off the log scale on both the x- and y- axes. Note: Using LOg does not cause the data to be altered, only the appearance of the plot changes. If the lower limit of the scale being logged is negative or zero, then PLT will rescan the data searching for the smallest positive value, and make that the lower limit.

You should also be aware of the fact that the size of the gap, created by the GAp command is affected by log scale. Thus for a non-zero gap, the sequence R X followed by LOg X produces a different range than LOg X followed by R X. In the first case, the data minimum and maximum values are found, and then gap added in linear space. Applying the LOg command does not change this scale. In the second case, the scale is first logged, then the data minimum and maximum values are found. At this point the correct gap for a log plot is added.

Web Page Maintained by: Dr. Lawrence E. Brown elwin@redshift.gsfc.nasa.gov