Distance Matrix for Aarhus Civil Defence Shelters and Buildings, 1951

The Distance Matrix Aarhus (DMA) dataset is a relational table of linked building–shelter pairs with associated Euclidean and network-based distance measures, created by the MELICA Project (Modelling Everyday Life in Cold War Aarhus) at Aarhus University, 2024–2027. It was produced specifically to support place-based spatial equity analysis of the Cold War civil defence shelter network in Aarhus, Denmark, as of 1951. The dataset was generated from three source layers: (1) georeferenced civil defence shelter locations (both public Betondækningsgrave, BDG, and private Sikringsrum, SR) digitized from the Aarhus Civil Defence Commission (CDC) collection held at the Aarhus City Archive; (2) building centroids for structures predating 1952, derived from the Danish Building and Dwelling Register (BBR/DBDR); and (3) a 2025 road network clipped from OpenStreetMap (OSM) to the 1952 urban boundary of Aarhus. Distance calculations — both Euclidean straight-line and routed network distances — were performed in R using the sfnetworks, RANN, and data.table packages. The scripts used to generate the dataset are available via GitHub: https://github.com/MELICA-AU/spatial-equity/blob/master/02_DistanceMatrix.Rmd. In its current version, the dataset consists of one row per building–shelter pair, covering 318 shelters (301 BDG, 17 SR) and all buildings within the 1952 Aarhus boundary with a construction date prior to 1952. Each record links a building to a shelter and records both Euclidean and network distance, the shelter's rank by proximity for that building, and the shelter's capacity used in gravity-model accessibility scoring. Format The dataset is published as a single CSV file (dma.csv), loadable directly into R or Python. In Python, you can use one of the following lines: # Parquet — fast, ~67 MB (recommended) dma = pd.read_parquet("https://zenodo.org/records/20234424/files/dma1951.parquet") # CSV alternative — universal but ~391 MB dma = pd.read_csv("https://zenodo.org/records/20234424/files/dma1951.csv?download=1") Column definitions are provided below and in the accompanying metadata file. Column descriptions building_key — integer key identifying the building in lieu of the alpha-numeric building_id shelter_key — integer key identifying the shelter provided in lieu of the occasionally alpha-numeric shelter_id net_m — routed network distance in metres between building centroid and shelter centroid, calculated via OpenStreetMap road network euclid_distance — Euclidean (straight-line) distance in metres between building centroid and shelter centroid shelter_rank — rank of the shelter for this building by network distance (1 = nearest) attractiveness — shelter attractiveness weight used in gravity-model scoring (based on shelter type and capacity); currently set to 1 for all pairs building_id — UUID of the building record in the Danish Building Register (BBR) (links to building register) shelter_id — integer identifier of the shelter in the MELICA shelter dataset (links to shelter register) shelter_capacity — number of persons the shelter is rated to accommodate Further reading on the dataset creation and methodology: [Authors], "Shelter for All? Spatial Equity and Civil Defence Planning in Postwar Aarhus." Journal of Digital History (forthcoming). [link to paper when published] Notes on distance measures Both Euclidean and network distances are provided because they bracket the plausible range of historical pedestrian travel. Euclidean distances represent an optimistic, obstacle-free scenario; network distances approximate actual walking routes but may overestimate friction in the historical city centre, where pedestrian shortcuts not captured by OSM were common. The 1952 urban boundary was digitized from a historical map of Aarhus. No digital road network from the 1950s exists; the modern OSM network is used as a conservative spatial proxy, justified by the enduring structure of Aarhus's core street grid. Disclaimer The shelter location data was digitized from archival sources by the MELICA project team and cross-verified against historical maps, archival photographs, and satellite imagery. Building data originates from the Danish Building Register (BBR), provided by third parties. The MELICA project does not vouch for the completeness of private shelter (SR) records, which are likely undercounted in the 1951 archive. Users are encouraged to consult the primary archival sources at the Aarhus City Archive and the project GitHub repository for full methodological details.