In the tension between large-scale analysis and accuracy - Identifying and analysing intra-urban (sub-)centre structures comparing official 3D-building models and TanDEM-X nDSMs. (June 2023)

• Record Type: Journal Article
• Authors: Standfuß, Ines; Geiß, Christian; Kühnl, Marlene; Droin, Ariane; Mast, Johannes; Wurm, Michael; Siedentop, Stefan; Heider, Bastian; Taubenböck, Hannes
• Is Part Of: Computers, environment and urban systems. Volume 102(2023)
• Publication Date: 2023-06
• Subjects: TanDEM-X -- Sentinel -- 3D-building models -- LoD-1 -- Urban mass concentrations -- Polycentricity -- Urban morphology; City planning -- Data processing -- Periodicals; Regional planning -- Data processing -- Periodicals; 303.4834
• DOI: 10.1016/j.compenvurbsys.2023.101953
• Languages: English
• ISSNs: 0198-9715

Abstract

Abstract: Intra-urban polycentricity has often been described by a balanced distribution of jobs/residences outside the traditional core cities in so-called (sub-)centres. Recently, this purely socioeconomic view has changed, so that centres are also increasingly understood as a physical manifestation of spatial development policies. Built-up volumes derived from 3D-building models are therefore frequently used instead of or as complement to employment/population figures when studying intra-urban polycentricity. However, such data are expensive and not available universally and permit only geographically limited investigations to date. To overcome this constraint, we investigate whether globally available and consistent TanDEM-X nDSMs (TDX) provide a valid data base for intra-urban polycentricity research based on built-up volumes. Our study focuses on four urban regions in Germany for which we have obtained official 3D-building models (LoD-1). For each study site, we derive aggregated built-up volumes from the TDX and the LoD-1 data and identify (sub-)centres. We use three centre identification algorithms to account for the diversity of methods and outcomes. We consider the LoD-1 (sub-)centres as reference and the TDX (sub-)centres as the entities to be reviewed. First, we quantify their spatial agreement and compare if polycentricity measures calculated based on both data sets lead to similar results. Second, we explore possible causes for discrepancies between the TDX/LoD-1 (sub-)centres. We find high spatial resemblances between TDX and LoD-1 (sub-)centres. Accordingly, we observe that polycentricity measures display similar trends among the two data sets. Nevertheless, we also show that the agreement between TDX and LoD-1 centres can be affected in uneven terrain, in sparsely built-up areas, and by the algorithms used to identify (sub-)centres. Overall, our results suggest that TDX nDSMs reflect the distribution of built-up structures in sufficient detail so that local-spatial densifications – here equated with (sub-)centres – can be appropriately studied. We therefore conclude that TDX data offer a great potential for the thematic domain of morphological urban analysis at large scale. Highlights: The suitability of TanDEM-X data for large-scale analysis of intra-urban polycentricity is tested. Centre detection capabilities based on 3D-building models and TanDEM-X data are compared. Similar polycentricity analysis results are achieved based on TanDEM-X data and 3D-building models. Factors influencing the agreement between centres from the two data sets are uncovered. The potential of TanDEM-X data for urban analysis is highlighted with a practical example.