An indicator set for capturing long-term open space fragmentation and urban development dynamics

Abstract

Open space preservation is an important spatial policy issue in developed, densely populated countries. Understanding open space dynamics in relation to urban development is critical to the development and evaluation of such policies. Starting from a conceptual model that hypotheses how open space will have developed over the past century we use a set of landscape ecology based indicators to capture these changes from a societal (perceptional) perspective. The indicators are applied to a newly compiled geodatabase of urban development in the Netherlands to show their performance in detecting and understanding past and future trends in open space provision. Our combined indicator set consists of land-use-based metrics that capture the area ratio of open space in relation to the total available space and total unit density of open and built-up patches. The methodology is designed to fit the low spatial and thematic resolution of land-use models as is exemplified by the inclusion of a future land-use scenario in the evaluation of open space development. The indicators confirm the hypothesised intrusion, intermediate and fill-up phases in open space fragmentation, and indicate a strong correlation between fragmentation and loss of open area. The results facilitate the distinguishing of compact urban regions from more fragmented counterparts while taking their relative state of urban development into account. The combined indicator set is useful to summarise and compare spatial development status between regions, while in combination with the advent of more detailed historic land-use data, our approach can be used to analyse open-space dynamics in different socioeconomic contexts.

Urban Landscape Fragmentation as an Indicator of Urban Expansion Using Sentinel-2 Imageries

“…The two values of the aforementioned indicators were computed after applying Equations 3 and 4. These findings corroborate the results of a great deal of the previous work linking urban landscape fragmentation with open space areas, showing that these two measurements have a strong relationship [2,8,14,34]. Based on the classification outcomes, the urban fragmentation map adequately demonstrates the cores of built-up areas, edges, and patches, as well as urban open spaces, as the first objective of this study.…”

“…Another important finding is that the openness index of Baqubah is 0.23, meaning that the city also has small patches of urban open space areas, making these spaces a target for future development. Typically, the ongoing fill-up stage of built-up areas will entirely urbanize small surviving open space areas [34]. However, the value of the openness index in Baqubah was low due to the urban extent in the city having the maximum saturation value for urban landscape fragmentation [33].…”

Spatial Heterogeneity Impacts of Urbanisation on Open Space Fragmentation in Hong Kong’s Built-Up Area

“…This is supported by our results that fragmentation index and urbanisation index values are noticeably higher in high-density Kowloon districts. It also echoes Wagtendonk and Koomen's findings that the open spaces in old towns are too small, non-intensive, and fragmented owing to the increasing scarcity of developable space [69].…”