Features can be addresses, roads, regions, etc.
Each layer in a GIS can be thought of as table in a relational database. Attributes represent a database table which is linked to a geographic layer. For example, a map showing census tracts which are color coded on the basis of the number of households residing in each tract. Thematic maps can also be applied to point locations, such as a map showing hospital locations where the size, color, and symbol indicate the type of hospital and the number of beds.