Additionally, 49,859 polygons representing urban and built-up areas were extracted using land-use maps for the 1980s and 2007 produced by the Korean Ministry of the Environment (KMOE). Here, the urban and built-up area was considered to include areas of housing, industry, commerce, entertainment facilities, transportation, public facilities, and construction. This included downtown districts or areas of completed development, but did not include small developments covering less than 1 ha.