ABSTRACT
This chapter introduces raster datasets with discrete variables, which are classified into a limited number of values. It uses classified land cover data from the National Land Cover Database (NLCD). The NLCD produces a standardized land cover data product for the United States. Often, land cover patterns can be seen more clearly if the land cover classes are aggregated into a smaller number of broader land cover types. The colors displayed in the map are heavily saturated—they appear bold and vivid. However, mixing many bright, saturated colors in a map can make it difficult to discern the underlying patterns. Another useful visualization technique is the “small multiples” approach, in which each land cover class is displayed in a separate map. Land cover patterns change over time as a result of urban growth, agricultural abandonment, clearcutting, and other land use activities.
