Using Satellite Imagery to Determine Spatiotemporal Patterns of Built-Up Land Use in Relation to the Coastline: An Example from Xiamen, China

This study used four Landsat-TM satellite imageries (1989, 2000, 2010, and 2018) to detect the spatiotemporal change characteristics of built-up land by using variance and correlation analysis to ensure the ecological capacity and urban sustainable development in Xiamen. The results show that during the rapid urbanization period of 1989 to 2018, a large amount of farmland (70.7%) and the water body (64.4%) were lost. Among them, 43.8% of farmland and 33.6% of the water body have been converted to built-up land, producing great pressure on ecological security and sustainable development. On spatial distribution pattern, this research found that the built-up land expansion in Xiamen mainly occurred along the coastline. Preliminary statistics found that the built-up land is mainly concentrated in the coastal zone as far as 5 km (reaches maximum density of 0.37 6 0.16) from the coastline. In this zone, the built-up land is most compact and intensive, whereas most of the new built-up land increased 5 km to 9 km away to the coastline. Variance analysis shows that built-up land density at all distances of buffer lines are very significant differences (P , 0.01), and the difference reaches the maximum of 0.289 at a buffer line of 7 km. Correlation analysis shows that the built-up land density varies significantly and negatively correlated with the distance to the coastline (P , 0.01), indicating that the farther away from the coastline, the smaller the density of built-up land is. The final regression analysis shows that a significant relationship with cubic regression equation occurs between the built-up land area in 1989, the built-up land density in 2018, and the distance from the coastline. Based on this analysis, the possible impact factors of the spatial pattern and approaches to a compact city are discussed.