In this example, merged polygons are created based on whether the adjoining input polygons have a database value within a specified interval.

A period ( . ) is used in the second and third TOPO CREATE MERGE commands in this example. Using a period instead of a named input layer allows the TOPO CREATE MERGE command to use the same layer as both input and output. This way we can continue merging different polygons, based on different intervals of the population (“pop”) value.