Spatial patterns and factors impacting settlements in Hongfeng lake watershed

This study aims to explore the spatial patterns of settlements and the underlying regional rules in the Hongfeng lake watershed, the results of which would provide a scientific basis for settlement optimization and regulation. Based on the Thematic Mapper (TM) images of Hongfeng lake watershed in 2000, 2005 and 2010, data for settlements, tourism-use areas, roads and rivers were extracted with the aid of Erdas8.5, ArcGIS9.3 software. The Hongfeng lake watershed was divided into a 1,000 m × 1,000 m grid with the percentage of settlements in each grid square calculated to determine settlement size-grade. The spatial distribution of settlements was converted to density figures using the Kernel Density function in Spatial Analyst Tools, and road and river buffer areas were determined. The results showed that in the Hongfeng lake watershed settlement numbers and area are rising (the number of settlement patches increased from 852 to 2,592, total area increased from 1,204.3 ha to 4,200 ha, and the average settlement density rose from 0.44/km2to 1.33/km2). A high area percentage of settlements and high settlement density are found in flat areas. Changes in the spatial distribution of the area of settlements and the settlement density are generally consistent. Small settlement patches grow rapidly. Settlement growth is mainly from farmland. Settlement expansion mainly occurs in scattered, banded and massive extensions. The spatial forms of the settlements are mostly scattered points, branches, and rules. Roads have a significant influence on settlement distribution. However, the influence of rivers is gradually declining. The total area of residential zones tends to decrease with increases in slope, but increases with the rate of settlement in 25°-80°areas.