1. A method for controlling the number of symbols of types (XYZ) i rendered on a map display, where i runs from 1 to N and N is the total number of selected symbol types, comprising: a) determining the total number of symbols S T ′&equals;SUM&lcub;S( XYZ ) i &rcub; for i&equals;1 to N, where &lcub;S( XYZ ) i &rcub; is the number of symbols of type (XYZ) i, and then first for i&equals;1; b) rendering FULL information for symbol type (XYZ) i on the map display and delivering S T &equals;S T ′ to step (e) if S T <S i (F) XYZ is TRUE, where S i (F) XYZ is a first threshold constant for symbol type (XYZ) i, or if S T <S i (F) XYZ is FALSE; (1) rendering MINIMUM information for symbol type (XYZ) i on the map display and delivering S T &equals;S T ′ to step (e) if S T <S i (M) XYZ is TRUE, where S i (M) XYZ is a second threshold constant for symbol type (XYZ) i, or if S i (M) XYZ is FALSE; c) delivering S T &equals;S T ′−S i (XYZ) i to step (e);, where S i (XYZ) i is the number of available symbols of type (XYZ) i ; and d) repeating steps (b)-(d) for i&equals;2 to N, thereby populating the map display with a controlled number of symbols.