Interval consumption is mapped into time-of-use periods using a TOU map. TOU maps define the TOU periods for each interval. TOU map data is structured in a format very similar to final measurement data, with specified intervals of time each designated to a TOU period (instead of a measurement value). For example, the table below lists a set of TOU map data and corresponding final measurements for a period of 4 hours on January 1, 2010.

Any type of final measurement can be mapped to a TOU period, including derived quantities. While the principal requirement for TOU Maps is to aggregate interval consumption into TOU periods for a Usage Transaction, the system has many zones in the user interface that display interval consumption using TOU periods.