An exploration of greenspace metric proximity and NDVI vs configurational accessibility from residential postcodes in the West of England

Fouad, Zaky; Sinnett, Danielle; Bray, Issy; McClatchey, Rachael; Reece, Rebecca

Abstract

Greenspaces are recognised as important features of an urban environment which are visited by residents for different purposes. This paper investigates the relationship between residents in the West of England and their surrounding greenspaces, by studying residents’ potential exposure to greenspaces as accessible destinations in the street network. This is evaluated through multiple spatial characteristics of greenspaces relating to their geographical location, thus, yielding different measures of greenspace exposure: the greenness of an urban space; the metric proximity to greenspaces; and the configurational accessibility of greenspaces. To define the potential users of greenspaces, the study uses a dataset of 617 postcodes of residents in the West of England, obtained from an online cross-sectional survey. From those postcodes, the study calculates ten greenspace exposure measures using ArcGIS Pro 2.9.5. These include: Normalised Difference Vegetation Index at four different Radii (NVDI 200m, NDVI 300m, NVDI 1000m, NVDI 2000m); the Euclidean distance to different greenspace sizes (nearest greenspace of any size, nearest greenspace of 0.5ha, 2ha, 10ha and 20ha); and the Network distance to the nearest greenspace of any size. The study proceeds to evaluate the configurational accessibility of the access-points into those greenspaces, using two Space Syntax measures: Normalised Choice radius 2000m and Integration radius 2000m. Findings suggest that the degree of greenness of a neighbourhood (measured through NDVI) correlates to the configurational accessibility of greenspace access-points (measured through Normalised Choice and Integration), while the strength of this correlation varies according to the catchment radius defined for the NDVI. It is also argued that closer greenspaces to the residential postcodes are easier to reach. Nevertheless, the easiness and directness (of navigating the network) relates less to the distance to smaller 0.5ha greenspaces, but this correlation is stronger when considering distance to the bigger greenspaces (10ha and 20ha). Finally, residents in this study could be travelling towards close-by greenspaces access-points that are configurationally more segregated than their homes which questions our perceptions of how to quantify greenspace proximity vs accessibility.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: 14th International Space Syntax Symposium
• Start Date: Jun 24, 2024
• Acceptance Date: Apr 16, 2024
• Deposit Date: May 3, 2024
• Keywords: Greenspace, NDVI, Proximity, Configurational Accessibility, Normalised Choice
• Public URL: https://uwe-repository.worktribe.com/output/11975811
• Publisher URL: https://cyprusconferences.org/14sss/