Map Classification and Layout
Map layer, that represent features in GIS, has more than its location and shape. The GIS layer can be associated with different information. For a river, this might include its name, length, and its water quality. For a county, this might include its population, ethnic group, household, income, age, and others. The information associated with a feature in a GIS is called an attribute. For example, population can be an attribute of a city, country, and other features. Feature attributes are stored in an attribute table. In an attribute table, each feature is a record and each attribute is a field. The attributes for all the features in a layer are stored in the same attribute table.