3.1.25. Shiftplot: shift the plotted spectrum for display purposes¶
This command shifts the observed spectrum as well as the model spectrum by adding a constant or by multiplying a constant, as far as plots are concerned. The true data files do not change, so the shift is only for representational purposes.
There are basically two options, indicated by the mode variable plotshift: For plotshift=1, a constant shift is added to the plotted spectrum of a given part of the data, for plotshift=2 the plotted spectrum is multiplied by the constant shift.
The multiplicative constant shift (plotshift=2) is generally preferred for log-log plots, while for linear plots a constant additive shift (plotshift=1) is preferred.
In the case of addition (plotshift=1), the addition constant is given in counts/s. This thus leads to a different (energy-dependent) constant being added to the plotted spectrum if the units are not in counts/s. For the multiplicative case this is of course not the case.
The following syntax rules apply:
shiftplot #i #r: #i indicates whether a constant should be added (#i=1) or multiplied (#i=2) to the spectrum and model. #r is then the constant to be added or multiplied by.
shiftplot [instrument #i1:] [region #i2:] #i3 #r: Shift the plot using a factor #r. Here #i3 (= plotshift) determines whether the constant is added (plotshift=1) or multiplied (plotshift=2). The optional instrument range #i1: can be used to select a single instrument or range of instruments for which the shift needs to be applied, and the optional region range #i2: the region for these instruments.
shiftplot 1 2.0: Adds 2 counts/s to the plotted spectrum. Since no instrument or region is specified, this applies for all spectra.
shiftplot 2 10.0: Multiplies the plotted spectrum by a factor of 10.0
shiftplot instrument 1 region 2 1 2: Adds 2 counts/s to the plotted spectrum for the data from instrument 1 and region 2.
shiftplot region 2:3 1 2: Adds 2 counts/s to the plotted spectrum for the data for all instruments and regions 23.