Dynamic mapping of urban regions: Growth of the San Francisco/Sacramento region
A methodology has been developed to document the tremendous growth large metropolitan regions have experienced over time. A GIS was used to compile a database of urbanization for the San Francisco/ Sacramento urban region spanning 140 years. Historical records, USGS topographic maps, aerial photographs, and Landsat imagery were used to identify the urban spatial extent. Digital transportation data and tabular census data were also incorporated into the database to provide a more complete picture of changes occurring over time. A time-series animation of urban growth for the urbanized region depicts the alarming growth patterns the area experienced between the mid-1800s and the 1990s. The same process is being used to document growth in other urban regions, such as the Baltimore-Washington area. This innovative use of temporal spatial data and animation focuses attention on the dramatic increases in urban development and the spatial patterns that have developed over time.