Urban expansion analysis of the Huang-Huai-Hai Plain region by DMSP/OLS nighttime light data

Urbanization, the conversion of other types of land to uses associated with growth of populations and economy, is a main type of land use and land cover change in human history. In recent 30 years, urban growth has been speeded up, and extreme stress to the environment has occurred in China. Based on the Defense Meteorological Satellite Program´s Operational Linescan System (DMSP/OLS) stable nighttime lights data, the urban extent in the year 1992, 1995 and 2000 in Huang-Huai-Hai Plain region, China were extracted by using the thresholding technique in this paper. Because the nighttime lights data acquired from 3 satellite platforms, and there is large difference between the same year data from different satellites, the data were interactively calibrated first. And then a unique threshold value was applied to all the data. The results show that the urban expands from the urban center to surrounding area in the Huang-Huai-Hai Plain region, and the total urban area increased from 8,349 km² to 12,727 km² from 1992 to 2000 with a mean annual growth ratio of 5.826%. The total urban area is close to the results from Landsat TM data with overall accuracy over 98%. However, the Kappa coefficient is low. The same threshold value results in over-extraction of urban extent in large-area urban and less-extraction of urban extent in small-area urban.