This software also enables you to do more than simply view data in its spatial context. It allows you to interact with data by selecting features and performing actions based on those selections. Spatial Data Spatial data contain the coordinates and identifying information for various map features. For example, the collection of points that represent park locations can be organized into a parks layer, the collection of lines that represent streets can be organized into a streets layer, and the collection of areas that represent census tracts can be organized into a tracts layer. A layer can be either static or thematic.
Thematic layers can use different graphical attributes to classify the features in the layer.
For example, a thematic area layer representing sales regions could use different colors to show the quarterly sales performance of each region. A thematic line layer representing highways could use different line widths to show the classes of roads. The second type of data used in a GIS is attribute data. For instance, the spatial data might represent a county and contain information for city boundaries, census tract boundaries, streets, and so forth. An attribute data set with population information for each census tract can be linked to a map by the corresponding tract value in the spatial data.