基于RS与GIS的农村居民点空间变化特征与景观格局影响研究

农村居民点作为乡村地域空间人口聚居形态,是乡村聚落景观重要组成部分,其空间布局、演变特征受自然、社会、经济多重因素的影响。利用都江堰市2005年和2010年两期遥感影像提取农村居民点、坡度、道路、河流等矢量数据,借助RS、GIS空间分析技术,定量研究都江堰市农村居民点的空间变化过程、格局和趋势,并选取景观格局指数对影响农村居民点布局特征的因素进行深入分析。结果表明:(1)2005年和2010年都江堰市农村居民点的空间分布总体上均表现出显著的聚集趋势,2010年农村居民点的聚集程度要比2005年高,但居民点集聚的空间态势没有发生明显变化,仍然集中在都江堰市的东南部;(2)坡度、道路和河流对都江堰市农村居民点的布局有显著影响,其中超过80%的居民点分布在0—10°坡度范围内,超过50%的居民点分布在道路500 m范围内,近60%居民点分布在河流1000 m范围内;(3)农村居民点空间布局除了受地形因素影响外,还与国家级风景名胜区、世界文化遗产区等保护政策,农村土地综合整治和灾后重建等规划因素密切相关。该研究以期为农村居民点动态变化监测、农村土地整理效果评价、新农村规划等理论和实践提供重要决策参考和技术支撑。

A study of spatial evolution characteristics of rural settlements and influences of landscape patterns on their distribution using GIS and RS

Forms of human habitation within rural settlements are a major component of rural landscapes. The spatial patterns and evolutionary characteristics of rural settlements are influenced by multiple factors, including natural, social, and economic elements. It is, therefore, important not only to properly identify and assess the spatial distribution patterns and evolutionary modes of rural settlements, but also to uncover causative laws and influential factors behind their evolution. This can facilitate scientific rural planning and enhance optimal distribution of urban and rural land resources. Our study is based on a series of digitalized vector data, including the locations of rural settlements, land slopes, rivers, and road networks obtained from remote sensing (RS) images of the city of Dujiangyan in Sichuan Province for 2005 and 2010. We applied analytical techniques derived from Geographic Information Systems (GIS) and RS to quantitatively analyze the processes, patterns, and trends of spatial evolution in rural settlements. Specifically, we explored landscape pattern indexes to examine in depth the factors influencing the distribution characteristics of rural settlements in the study area. Our results showed that: 1) In general, while there was significant clustering in the spatial distribution of rural settlements in Dujiangyan during both 2005 and 2010, this settlement pattern was even more significant in 2010. Along with an increase in the spatial scale, the degree of the clustering tendency also increased, reaching a maximum value at a scale of 13 km. 2) The presence of land slopes, roads, and rivers significantly influenced the distribution of rural settlements in Dujiangyan as evidenced by the following findings. More than 80% of settlements were located in areas with slopes of less than 10 degrees; over 50% of settlements were located within 500 m from a road network; and almost 60% were distributed within 1000 m of a river. 3) In 2005 as well as 2010, there was no obvious change in the concentrated locations of clusters, which were consistently found in the southeastern region of Dujiangyan City. However, during both time periods, fewer settlements were found in the townships of Hongkou, Longchi, and Qingcheng Mountain. The reason for this imbalance in the spatial distribution of rural settlements was that besides the influence by natural factors such as the landscape, the distribution patterns of rural settlements in Dujiangyan were also closely associated with several planning elements. These included a policy of protecting national regions of scenic interest and a World Cultural Heritage site located in the city, the rural land comprehensive consolidation projects and post-earthquake reconstruction planning. 4) Based on the above findings on factors that influence the distribution of rural settlements, our research suggests that comprehensive consideration of topographical and geological conditions is required for optimal adjustment of rural settlement patterns. Scientific planning procedures can promote the relocation of rural residents from villages to townships and urban areas, and help to lessen disruption in environmentally protected regions. They can also reinforce the effective use of land resources and increase land supporting capabilities. We expect our research to provide a methodological reference for similar research conducted in the future. It can also provide a theoretical and practical reference for rural land-related decision-making and technical support, for example, dynamic monitoring of changes in rural settlements, assessments of rural land consolidation, and the "New Socialist Countryside" rural planning policy.