PLT in Fplot: Some Idiosyncrasies
Like xspec, the plotting ftool fplot uses internal, "pre-programmed" PCO files, though not as extensively. Here's a typical run:
kaah[45]%
Name of FITS file and [ext#] data3_hard.lc
Name of X Axis Parameter[error] TIME
Name of Y Axis Parameter[error] up to 8 allowed RATE[ERROR]
Lists of rows[-]
Device: /XWindow, /XTerm, /TK, /PS, etc[?] /xw
Any legal PLT command[]
And here's some explanation:
- fplot offset=yes:
You should explicitly set the hidden parameter offset to be "yes" if you want the first x-value to be subtracted from all the x-values to produce an x-axis starting at zero (the default is "no"). This subtraction will occur before PLT is called.
- data3_hard.lc:
Self-explanatory.
- TIME:
The column in the FITS file to be used as the x-axis. As we saw in the section on QDP, PLT needs to know whether the second column it encounters is either the x-error array (if there is one) or the first y-array. This is done by enclosing in brackets the name of the column containing the x-error array. Note that fplot is case-sensitive, so you might want to check the column names beforehand with the flcol ftool.
- RATE[ERROR]:
In this example, the y-array RATE does have an associated error array, called ERROR.
- Lists of rows[-]:
This allows part of the file to be plotted, if desired. The removal of array elements occurs before PLT is called.
- Device: /XWindow, /XTerm, /TK, /PS, etc[?] /xw:
Self-explanatory.
- Any legal PLT command[]:
An option for passing a command to PLT before the plot appears. Note that because of the way fplot is written, using this option overwrites fplot's internal PCO file which takes labels for the axes from header information in the file itself.
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