[spatial analysis]
A method of defining the rings in an analysis so that the values inside the rings are cumulative. For example, if you had an analysis with three concentric rings and 10 households in each, the total number of households for ring 1 would be 10, the total for ring 2 would be 20 (ring 1 + ring 2), and the total for ring 3 would be 30 (ring 1 + ring 2 + ring 3).