If any of interpolation methods 1 ('linear with averaging'), 3 ('staircase with averaging'), and 5 ('natural cubic spline with averaging') is used, the number of returned values is one less than the number of targets and the target values must be given in increasing order. The values returned are the average heights of the interpolation function on the intervals determined by consecutive target values.
1. ('linearra batezbestekoarekin'), 3. ('mailakatua batezbestekoarekin') edo 5. ('spline kubiko naturala batezbestekoarekin') interpolazio-metodoetako bat erabiliz gero, itzulitako balioen kopurua helburu kopurua baino bat gutxiago da, eta helburu-balioak goranzko ordenan eman behar dira.