An area of specific interest can be extracted from a signal by use of the jetsubset function. The standard set splits a signal into several parts. Then using the jetmerge function recombines these parts to give new signals.

This can be done either at the IDL expression window, or using a simple expression. To extract the points between two X values type the command of the form NEW=JETSUBSET(SIGNAL1,'X:(C1):(C2)',SIGNAL1_TIME,SIGNAL1_X) into the IDL expression box. C1 and C2 should be replaced by the the end points of the region of interest. These are taken to be x values but indices can be entered using square brackets. Note that these indices are zero based e.g. C1=[0] refers to the first point.

If C1 is left blank then the lower limit is taken to be the start of the signal, and for C2 it is taken to be the end of the signal. A similar expression is used for subsets in time; NEW=JETSUBSET(SIGNAL1,'T:(C1):(C2)',SIGNAL1_TIME,SIGNAL1_X) and for 2D signals the SIGNAL1_X arguement is a dummy arguement and can be left out.

A shortcut to each of these is available from the Simple expressions dialogue. F(t) for the 2D subset command and F(t,x) for the to 3D commands.

An example of this and the jetmerge proceedure is given by the standard set subset_merge.jss

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