深圳市福田区三维城市景观格局变化特征

城市景观是景观变化最快的类型之一,建成景观与绿地景观格局和功能的相互影响及空间配置是城市景观优化的核心。在紧凑型城市快速发展过程中,城市垂直方向增长成为主要扩展方式。如何定量分析三维城市景观格局变化,为城市景观优化提供科学依据还有待深入。选取深圳市福田区,以高分辨率遥感数据和建筑普查数据为基础,运用景观格局指数和景观连通性等方法定量分析建筑景观和绿地景观变化及空间影响。研究结果表明:(1)2003—2016年,福田区建筑景观主要表现为垂直向的立体扩展模式,新增建筑主要为高层和超高层建筑,建筑平均高度增加6.53 m,立体空间体积增加135.58×10~6 m~3,建筑密度仅增加2.42%,建筑景观高度差异逐渐增大,呈现出明显的三维空间异质性。(2)2003—2016年,建筑景观格局由"阶梯式"转变为"金字塔"形,受益于建筑景观的垂向增长,建成景观与绿地景观比例由1.20∶1调整为0.99∶1,建成景观减少4.03 km~2,绿地景观增加2.80 km~2。(3)建成景观的三维立体化释放了绿地景观用地空间,同时也限制了绿地景观的外部连通性,绿地景观连通性较低,大型绿地斑块间缺乏廊道连通,呈现孤岛化。研究可为城市景观空间优化和国土规划等实践提供科学依据。

Three-dimensional urban landscape pattern changes: A case study in the Central Business District of Futian, Shenzhen

Landscape changes associated with rapid urbanization are one of the most dramatic forms of land transformation. It is essential to quantify landscape patterns and their changes for urban landscape management policy-making. In the compact city, the growth of building height is the main form of landscape expansion. How to quantify the three-dimensional (3D) landscape patterns and their changes has become a hot topic in landscape pattern analysis, which is vital to understanding ecological consequences of urbanization and the interaction between architectural landscape and green infrastructure landscape. However, further research is needed to improve 3D landscape pattern quantitative analysis in comparison to previous studies that mainly focused on urban horizontal expansion. The focus of this paper is the vertical and horizontal urban landscape changes based on high-resolution remote sensing images and building census data by employing 3D landscape metrics and the landscape connectivity index to quantify the rapid landscape pattern changes in the Futian District, Shenzhen City. The results showed that (1) vertical growth was the main expanded feature of architectural landscape from 2003 to 2016. The high-rise buildings (27-99 m) and super high-rise buildings (over 100 m) dominate architectural landscape in Futian. These changes resulted in an increase of 6.53 m in the average building height and an increase of 135.58×10⁶ m³ in building volume. However, it only increased the building coverage ratio by 2.42%, which indicated typical three-dimensional spatial heterogeneity in Futian. (2) The architectural landscape pattern turned from the "Stepped" style into the "Pyramid" style. Because of the vertical expansion of the architectural landscape, the proportion of built-up landscape and green landscape changed from 1.20:1 to 0.99:1, which resulted in a decrease of 4.03 km² of built-up landscape and an increase of 2.80 km² green landscape. (3) The transformation of landscape type and its spatial influence showed that the three-dimensional transformation of the built-up landscape released the space for green landscape, but also restricted the external connectivity of the green landscape, which led to the Central Business District (CBD) having low-level landscape connectivity. The green landscape patches are isolated by high architectural landscape. There are inadequate corridors to connect green patches. Our results provide a scientific basis for urban landscape optimization and land use policy-making.