GIS-based revision of a WUDAPT Local Climate Zones map of Bern, Switzerland

• Published in: City and environment interactions 2024-01, Vol.21, p.100135, Article 100135
• Main Authors: Wellinger, Noémie, Gubler, Moritz, Müller, Flurina, Brönnimann, Stefan
• Format: Article
• Language: English
• Subjects: Decision tree; Geodata; LCZ; LCZ generator; Urban canopy parameter; Urban heat island
• ISSN: 2590-2520; 2590-2520
• DOI: 10.1016/j.cacint.2023.100135

•GIS-based workflow to enhance LCZ maps produced with the LCZ-Generator.•Accuracy assessment and revision of the map using urban canopy parameter geodata.•Improved mapping of small-scale structures with a notable impact on local climate.•Straightforward workflow, customizable for other cities. Urban areas are particularly affected by heatwaves through the intensification of heat stress by the urban heat island effect. For effective climate change adaptation, information about microscale surface cover, structures, and human activity in cities is needed to depict the underlying causes of urban heat stress. The framework of “Local Climate Zones” (LCZs) classifies and standardizes urban areas based on such characteristics. To date, most LCZ mapping workflows use satellite imagery as input. The resulting maps may lack some important details, and thus benefit from the use of additional geodata. We introduce a novel approach that combines the geodata of urban canopy parameters with the remote sensing-based LCZ map of Bern, Switzerland. City-specific urban canopy parameters are calculated and used to adjust established value ranges, if necessary. The most common misclassification patterns are identified and misclassified pixels are corrected using a decision tree and k-nearest-neighbor algorithm. Results show that the conformity with the urban canopy parameter values markedly increased, especially in the distinction of water surfaces, non-built areas, and building height. However, for high-resolution LCZ maps, this also leads to unnecessary heterogeneity, which may require further postprocessing. Given sufficiently available urban canopy parameter data, the proposed workflow is simple and easily adaptable for other cities. It could prove useful in urban climate studies and city planning to enhance an existing LCZ map in a contextualized manner quickly.