Geospatial Analysis of the Urban Ecosystem
Supporting healthy, liveable, and equitable cities
Cities are complex ecosystems, where people, nature, and the built environment interact in a variety of ways. Today, cities around the world are grappling with societal and environmental challenges arising from climate change and urbanization. Notably, cities often experience higher temperatures than surrounding areas (a phenomenon known as the “urban heat island effect”), which can have negative impacts on human health and ecosystem functioning. Additionally, cities face issues like air and water pollution and biodiversity loss. Moreover, cities can be sites of considerable inequalities; it is often the poorest populations who are most exposed to environmental harms. Innovative approaches are required to make visible and address these inequalities.
Geospatial tools and techniques can be used to map and analyse urban ecosystems and their changes over time. Within the CGIS group, we focus primarily on the crucial role of urban green and blue spaces. Urban vegetation can help address urban environmental and social challenges by reducing temperatures, filtering the air, and providing recreational opportunities. Increasing nature in cities, particularly in areas most at risk of environmental harms, can therefore be a cost-effective way to address urban inequalities.
How does CGIS study urban ecosystems?
Geospatial analysis
Our research group mainly makes use of Geographic Information Systems (GIS) to perform geospatial analyses and mapping based on the different inputs, derived from remote sensing images and field surveys. GIS enables the exploration and comparison of ecological and social phenomena on the ground. For instance, it can be used to assess who has access to urban green spaces and who does not. In many cases, we focus our analysis on the urban ecosystems where vulnerable groups (like children and the elderly) live, work, and play, by assessing green provision around schools and elderly homes.
Bringing in citizen perspectives
Our examination of urban inequalities goes beyond observations of the surface. People’s perceptions and experiences of urban environments play a major role in how people use and benefit from these spaces. Participatory GIS surveys make it possible to integrate people’s experiences into assessments of urban ecosystems by asking survey respondents about the places they visit and their experiences of those places. PPGIS has been used in our research group to understand which green spaces people visit and how they experience those spaces.
Similarly, social media data can be used to crowdsource opinions on urban ecosystems by extracting keywords in user reviews or by analysing photos shared on popular photo sharing platforms, like Flickr. These insights help to provide a quality layer to spatial assessments of urban ecosystems and contribute to the societal call to improve public participation in urban planning and research.
Combining GIS analyses with qualitative methods
Sharing and discussing the outcome of our research is an essential part of our activities. CGIS organizes workshops and focus groups to engage a variety of stakeholders, including planners and public officials, in discussions around our research. Highlighting the uncovered inequalities to stakeholders can introduce a crucial equity perspective to the discussion, often overlooked in urban planning. Ultimately, our findings can influence and guide urban spatial policy and planning.
An interdisciplinary approach
Given that urban ecosystems include people, nature, and the built environment, an interdisciplinary approach is essential in our research. For this reason, our research group often works in collaboration with others, such as the Cosmopolis Center for Urban Research (Geography Department), the Interface Demography research group (Sociology Department), as well as the Building, Architecture and Town Planning (BATir) and the Socio-Environmental Dynamics (SONYA) research groups of the ULB. In fact, some CGIS members have double-affiliations with these groups, conducing their research between different departments.