In Cartographica, data is organized into Layers. A Layer consists of one type of data (point, line, area, or imagery), and contains one or more features of each type. Each of these features usually contains geospatial information (one or more sets of X,Y and possibly Z coordinates) as well as optional reference data that describes characteristics of the features in the layer. It is the attachment of the reference additional data to the geospatial information that makes a GIS like Cartographica so powerful. By using geospatial data, correlations can be made between information in the reference data, leading to informative maps and insightful data analysis.