Basic Categories of Cartographic Symbolization: Areal, Line, and Point Symbols

Symbolization can take on a range of functions on a map but it should be clear and easily understood by the user. In many ways, symbolization can be regarded as the coding of map features to communicate meaning.

The challenge in cartographic symbol design is that four categories of data must be represented on maps by only three basic symbol types: point, line, and area.

Point symbols

A point symbol represents a geographic feature or event characterized by location and attributes. Its location can be represented by a single “x, y” coordinate pair, while attributes can be many. For example, a populated place or a mine site can be represented by a point symbol.

Line symbols

A line symbol represents a geographic feature characterized by linear dimension, but not area. In digital technology, a line is a sequence or stream of point coordinates with a node at each end (vector data) that symbolizes a linear feature such as a road, river, or boundary.

Area symbols

Area symbols are used to illustrate the complete area like forest, ocean, desert, etc. An area symbol represents a closed geographic surface feature, two-dimensional geometric region, or a polygon. A census division, a lake, or any geographically defined surface is examples of area features.

The following diagram sets out a range of ways in which you can modify the symbolization of a feature to give it different meaning.