The delimiting of service areas determining the need for residential facilities at the district or community level shall be based on the Petaluma general or environmental design plans; if applicable. The "Planning Neighborhood" will normally provide the basis for estimating the number of families to be served by facilities at the local level. A "Planning Neighborhood" shall insofar as possible exhibit the characteristics in Sections 20.32.410 through 20.32.430. (Ord. 1046 NCS §1 (part), 1972; prior code §22.7.1203.)