View-based greenery: A three-dimensional assessment of city buildings' green visibility using Floor Green View Index

Vegetation provides many environmental benefits to the city, and daily access to vegetation contributes to the well-being and psychological status of urban residents. Understanding and measuring urban dwellers' view-based exposure to greenery has become an important and much needed task for assessing the quality of urban life. This paper presents a new quantitative and objective indicator, the Floor Green View Index (FGVI). It is defined as the area of visible urban vegetation on a particular floor of a city building. The method for estimating FGVI consists of three steps: creating observation points and setting observation platform for each detected floor, conducting viewshed analysis and extracting visible urban green space, and computing the Floor Green View Index. The method is proposed and tested through a case study of the Lujiazui region, Shanghai, China, using airborne Light Detection and Ranging (LiDAR) data and aerial photographs. The new indicator and methods can be used as powerful quantitative tools for urban design, landscape architecture, urban green planning and management.