An interval data curve is mapped into time-of-use periods using a TOU map. The TOU map used by the calculation rule for mapping interval data curve values to time of use periods is defined directly on the calculation rule.

TOU map types define attributes shared by TOU maps of a given type. The essential attributes of any TOU Map Type are the interval sizes between TOU map data rows, associated TOU map template(s) to use, and whether the TOU data will follow any seasonal time shifting.