Understanding contemporary demographic and economic drivers of household mobility and their policy implications Hoon Han, Matthew Ng, Laura Crommelin, Glen Searle, Brian Lee, Parian Hoseini Ahuri Final Report, 2025 From the AHURI Inquiry: Inquiry into projecting Australia’s urban and regional futures: population dynamics, regional mobility and planning responses What this research is about This research looked at why people move between urban and regional Australia, and identified the social, economic, demographic and policy factors driving these population shifts.
Scale effects of the spatiotemporal relationship between nighttime light and population activity intensity: a case study in Shanghai, China Xiangzhong Guo, Tao Lin, Yicheng Zheng, Matthew Ng, Junmao Zhang, Hongkai Geng, Zixu Jia, Jing Lin, Yuan Chen, Hoon Han, Christopher Pettit Giscience and Remote Sensing, 2025 Understanding the spatial distribution and temporal dynamics of population activities is critical for advancing interdisciplinary research in economic development, climate change, environmental management, and urban sustainability. Although nighttime light remote sensing data has been widely used to represent human activity, limited research has examined their spatiotemporal relationship between static nighttime light (NTL) and dynamic population activity intensity (PAI). This study integrates high-resolution SDGSAT-1 NTL imagery with hourly Baidu User Density data to investigate the multiscale spatiotemporal relationship between NTL and PAI in Shanghai, China. Using bivariate spatial autocorrelation and a multiscale analysis framework, we assess spatial association across four different time segments: satellite transit, nighttime, daytime, and whole day. At the 200m scale, the spatial association between NTL and PAI is both positively correlated and temporally stable, as evidenced by global Moran's <i>I</i> value (<i>p</i> < 0.001) ranging from 0.38 to 0.43 and a clustering consistency index of 0.88 across different time segments. Extending the analysis to ten different spatial scales (200m–2000m) reveals scale effects in the spatiotemporal relationship. While clustering patterns between NTL and PAI vary with spatial scale, temporal stability remains consistently high within each scale, with clustering consistency indices ranging from 0.88 to 0.96 across different time segments. A semi-variogram-based method identifies 1000-1400m as optimal spatial scale range at which NTL can best represent PAI, with 1200m being the optimal scale suitable for this study. These findings promote the use of NTL data in capturing the spatiotemporal dynamics of human activity, underscore the temporal stability of the relationship between NTL and PAI, and highlight the critical role of spatial scale selection in NTL-based population research.
From urban clusters to megaregions: mapping Australia’s evolving urban regions Matthew Kok Ming Ng, Zahratu Shabrina, Somwrita Sarkar, Hoon Han, Christopher Pettit Computational Urban Science, 2024 This study employs percolation theory to investigate the hierarchical organisation of Australian urban centres through the connectivity of their road networks. The analysis demonstrates how discrete urban clusters have developed into integrated regional entities, delineating the pivotal distance thresholds that regulate these urban transitions. The study reveals the interconnections between disparate urban clusters, shaped by their functional differentiation and historical development. Furthermore, the study identifies a dichotomy of urban agglomeration forces and a persistent spatial disconnection between Australia’s wider urban landscape. This highlights the interplay between urban densification and peripheral growth. It suggests the need for new thinking on potential integrated governance structures that bridge urban development with broader social and economic policies across regional and national scales. Additionally, the study emphasises the growing importance of national coordination in Australian urban development planning to ensure regional consistency, equity, and productivity.
A participatory mapping approach to capturing perceived walkability Josephine Roper, Matthew Ng, Jonathan Huck, Christopher Pettit Transportation Research Part A Policy and Practice, 2024 We present a novel method for capturing citizens’ views on perceived walkability. Peoples’ decisions to use any transport mode are determined by perceived accessibility, thus perceived walkability is vital to the decision to walk for transport. To date, approaches to understanding perceived walkability, such as detailed ‘walkability audit’ instruments, have been difficult to scale and linked only to respondents’ residential locations. In contrast our research uses an online mapping tool designed to rapidly capture vague knowledge about places. Respondents use a map interface to spray-paint the most and least walkable areas across the city of Sydney, Australia, along with defining the area they regularly walk from home and where they would be willing to walk. They also provide free-text input to explain their responses. This approach enables data collection of respondents’ holistic understanding of the walkability of different areas based on the local knowledge and experience of the city. Pilot results together with qualitative analysis of text submitted in response to open ended questions are presented to demonstrate the feasibility, face validity and potential of the method. A comparison with an accessibility-based walkability index, WalkTHERE, for Sydney is shown. Results are broadly aligned, but the perceived walkability results presented highlight the negative environmental quality of walking near high-traffic roads and the positive aspects of natural and water views, which are not captured in this walkability index. Perceived walkable areas around the home were on average similar in overall area to the common standard of 15-minute buffers, but longer in their longest dimension, and have irregular shapes. Detailed methodology for analysis of the online mapping inputs is provided. This method has potential for rapid yet rich data collection, particularly when used together with a walkability model to understand differences which can point to localised problems with walking environment quality.
Incorporating diminishing returns to opportunities in access: Development of an open-source walkability index based on multi-activity accessibility Josephine Roper, Matthew Ng, Christopher Pettit Journal of Transport and Land Use, 2023 In this paper, we argue for an explicit decoupling of “walkability” and “walking behavior” and for the advantages of a definition of walkability based on access. This provides impetus for a new approach to constructing and using walkability indices, combining accessibility theory with a goal of comprehensiveness and communicability. Diminishing returns-to-opportunities can be used to map the infinite origin-destination gravity potential space to a finite scale thus creating an easily communicable metric, or metrics. In addition, this method can be applied to any mode and applied to multiple destination types singly or combined. Application of this theoretical approach is demonstrated through the creation of a novel comprehensive open-source transport walking potential index, WalkTHERE. A 0-100 scale is used to represent the percentage of people’s total needs potentially accessible by walking. The index is applied to eight Australian and two European cities, and the specific data considerations and parameters chosen are described. Significant disparity is shown in walking access between different destinations within cities, and in walking access between cities. Walking access to recreational opportunities is highest, followed by education and shopping, with very little employment access for most residents. Avenues for expansion and further validation are discussed.
COLOURING AUSTRALIA: A PARTICIPATORY OPEN DATA PLATFORM J. Roper, P. Hudson, H. Petersen, C. Pettit, T. Russell, M. Ng ISPRS Annals of the Photogrammetry Remote Sensing and Spatial Information Sciences, 2022 Colouring Australia is a digital platform for collecting and visualising building level information across several Australian cities. It provides a valuable resource for bringing together data on building age, material, sustainability ratings, walkability and other key metrics as we plan for net zero cities. Colouring Australia comprises part of the international Colouring Cities Research Programme, which supports the development of open-source platforms that provide open data on national building stocks. In this paper we outline the technical architecture of the platform, and the development and visualisation of a building level walkability metric based on pedestrian access to destinations. This platform provides a useful digital tool for planners to understand which parts of the city are walkable and in turn this can support future active transport programs and policies. Future research will be to validate this novel walkability index through a series of stakeholder and public workshops using the Colouring Australia platform in an interactive tabletop environment where usability testing can be undertaken.
