2000—2015年深圳市建设用地坡谱演变研究

在受地形约束的快速城市化地区,建设用地水平扩张常伴有垂直爬坡过程。通过分析建设用地坡谱曲线形态及其变化特征,有助于认识该过程的时空分异及演变规律,进而科学指导相关国土规划实践。论文以深圳市及其所辖10个区为例,利用DEM及2000—2015年遥感影像构建地面坡谱和4期建设用地坡谱,借助陡峭度、均匀度、累加关键值等坡谱研究手段,分析该市建设用地坡谱演变特征。结果表明：深圳市建设用地坡谱变化特征总体表现为爬坡与填海共存,且以爬坡为主,总体爬坡速度保持相对稳定;该市各辖区建设用地坡谱曲线呈现不同变化特征,可归纳为爬坡主导型、填海主导型、混合型和稳定型;各辖区建设用地布局均集中于平缓区域,建设用地上坡程度整体属于轻度至中度,建设用地主流上限坡度分布范围为4°~14°,建设用地极端上限坡度分布范围为7°~20°。深圳市仍将面临建设用地继续爬坡的压力,相关坡度上限标准的科学制定与严格执行是把控建设用地爬坡进程的关键。

Study on the Evolution of Construction Land Slope Spectrum in Shenzhen during 2000-2015

The horizontal expansion process of construction land often occurs with vertical climbing process in the rapid urbanization area which constrained by topographic factor. Slope spectrum is a useful tool that can help people understand the spatial-temporal characteristics and evolution laws of the vertical climbing process of construction land. A lot of useful knowledge needs to be mined from the morphological characteristics of slope spectrum curve to guide planning makers to make more scientific land use planning. In this paper, taking Shenzhen and its 10 districts as examples, SRTM DEM data and Landsat TM/OLI images in four periods from 2000 to 2015 were used to build the background land surface slope spectrum and construction land slope spectrum. Aiming to study the morphological characteristics and evolution laws of the construction land slope spectrum, some qualitative empirical knowledge and a series of quantitative indices based on slope spectrum theory were defined, such as steepness of slope spectrum, evenness of slope spectrum, and forward cumulative critical value of slope spectrum. The results show that: 1) The overall expansion rate of construction land in Shenzhen was decreasing and tended to be stagnant from 2000 to 2015. The main spatial pattern of construction land change is characterized by the coexistence of climbing and reclamation and is dominated by stable climbing process. 2) Each municipal district shows different characteristics of construction land slope spectrum which can be summarized as four types: climbing dominated type such as Longhua District, reclamation dominated type such as Nanshan District, climbing and reclamation mixed type such as Yantian District, and stable type such as Futian District. 3) The steepness of slope spectrum is below 0.2, the evenness of slope spectrum is between 0.4 and 0.8, the main upper limit slope of construction land is between 4° and 14°, and the extreme upper limit slope of construction land is between 7° and 20°. In other words, for Shenzhen and its districts, construction land tend to congregate in flat region, and the climbing degree of construction land is not serious. Besides, all the quantitative indices of slope spectrum in the southern municipal districts are larger than those in the north. This research suggests that Shenzhen will still face the pressure of construction land climbing in the near future. It is very necessary and urgent to set scientific and strict standards of upper limit slope for construction land climbing, and it is also important to enforce these standards strictly.