Remote Sensing and Modeling in Regional Land Cover Change Study

This paper summarises the general pattern of urban land-cover change in the Northeastern Illinois between 1972 and 1997 using Landsat acquired remotely sensed images. The region, centred by the city of Chicago, experienced dramatic land cover change in the past decades. Accompanying the redistribution of population and decentralisation of metropolitan functions are the tremendous growth and development of outlying suburban areas. Comparison of classified land cover data of 1972, 1985, and 1997 demonstrates that urban land expansion dominated the regional pattern of land cover change. Between 1972 and 1985, urban land increased by 14.5%. Urban land increase and suburban sprawl accelerated to about 30% between 1985 and 1997. Within the 25 years between 1972 and 1997, urban land increased about 49%. Most of the suburban land expansion occurred by consumption of agricultural land in the outer-ring and collar counties. About 22% and 20% of agricultural land were converted into other land use in the time periods between 1972 and 1985, and 1985 and 1997, respectively. A 37% decrease of agricultural land was observed from 1972 to 1997. Natural areas, on the other hand, declined 7.6% from 1972 to 1985, and 14.5% from 1985 to 1997. In total, 21% of natural areas were converted into other types of land covers. Many municipalities, particularly in the collar counties of Chicago, have expanded their territory by annexation. The expansion of the municipalities partially reflects the extent and potential of urbanization in the suburban areas.