Feature data

In geographic information systems, a feature is an entity with a geographic location, typically describable by (for example) points, lines, arcs, or polygons. Roads, bodies of water and cadastres are examples of feature data. Features are usually labeled.

Feature types
The definition of features that are related by membership of a common theme is a feature type, though there are a number of terms for this characteristic, including category, feature class, group, layer, level, object, and theme.

Layer is the traditional term of choice, but use of this term has declined as data has become more object oriented and less concerned with cartographic layering.

Feature types can be used to create a hierarchical structure. For example, a dataset consists of types called highways, streets and lanes. These types may be grouped together under a category called "Roads".