城市建筑迎风面积密度矢量/栅格计算模型对比研究

城市建筑迎风面积密度（Frontal Area Density,FAD）作为重要的城市形态学参数之一,对其定量分析与制图,对城市微气候研究有着重要意义。为了找出高效可靠的方法分析城市建筑FAD的分布情况,本文以福建省晋江市为例,选取了矢量计算模型和栅格计算模型对FAD进行模拟,从计算效率、不同尺度和不同土地利用类型上,对结果进行对比分析。研究表明:计算效率上,矢量模型比栅格模型高。在城市尺度上,栅格模型与矢量模型模拟结果与宏观建筑分布特征一致,二者皆适用;在街区尺度上,栅格模型模拟结果比矢量模型更符合建筑分布规律。栅格模型的计算结果较矢量模型稳定,受分辨率影响小。在不同土地利用类型上,对于建筑分布稀疏区域2种模型皆适用;而对于建筑密集区,如商业区、城市住宅区等,栅格模型计算结果更优。

Study on Comparison of Vector/Raster Calculation Model of Frontal Area Density of Urban Buildings

Frontal Area Density (FAD) of urban buildings is one of the important parameters of urban morphology. Therefore, the quantitative analysis and its mapping play a significant role in the field of urban microclimate research. It helps climatologists and urban planners mark out the detected ventilation paths, which could improve the thermal conditions in the inner city. In order to determine an effective and reliable method of analyzing the distribution of urban FAD, we took Jinjiang city of Fujian province as an example. We selected the vector and the raster calculation model to simulate FAD. Considering computational efficiency, we analyzed the obtained results from various scales and land use types. Two computer models were developed based on GIS and geodatabase. Each calculation model has an advantage of its specific data type. Mean, maximum, minimum and standard deviation of FAD for some chosen sample areas in Qingyang subdistrict were calculated and there were significant differences between selected areas. The research shows that the vector model is more efficient than the raster model. At the urban scale, the simulations of the vector and raster models are both consistent to the distribution characteristics of buildings at the macro level. At the neighborhood scale, the results of the raster model are more in line with building distribution than the vector model. When the scale of the area is reduced, the differences between two models increase. The raster model is more stable than the vector model, and is less affected by the resolution. In different land use types, the mean FAD values in business districts and urban residential areas are higher than the others. In the raster model, the average difference between the two resolutions of urban residential area is the lowest. In the vector model, the average difference of the green space is lower than the other three land use types. Thus, the two models are applicable for sparse distribution areas, but for building dense regions, such as business districts and city residential areas, the raster model performs better.