Dynamics of urban growth in the Washington DC metropolitan area, 1973-1996, from Landsat observations

Like other human-induced landcover changes, urbanization represents a respo nse to specific economic, demographic, or environmental conditions. We use the Washington D.C. area as a case study to relate satellite-derived estima tes of urban growth to these economic and demographic drivers. Using the La ndsat data archive we have created a three epoch timeseries for urban growt h for the period 1973-1996. This map is based on a NDVI-differencing approa ch for establishing urban change filtered with a landcover classification t o minimize confusion with agriculture. Results show that the built-up area surrounding Washington DC has expanded at a rate of similar to 22 km(2) per year during this period, with notably higher growth during the late-1980s. Comparisons with census data indicate that the physical growth of the urba n plan, observable from space, can be reasonably correlated with regional a nd national economic patterns.