The function InterpolXYTable interpolates a function defined by the open array of irregularly spaced pivoit points (parameter XYTable) at the x position given by Arg. The x and y coordinates of the pivot points are defined by the two-dimensional array XYTable. The first column of the array contains the x values, the second column the y values. Each row of the array specifies a pivot point.
If the argument Arg is less than lowest x value (i.e. XYTable[0,0]) or greater than highest x value (XYPivots[0,length(XYPivots)]) the returned function value is extrapolated using the first or the last line segment, respectively.