Extended Data Fig. 3: An overview of the 1936/1938 aerial survey⁷ and the new datasets available from this study.

(a) Locations of the 5,507 high-oblique aerial photographs acquired during the mapping campaigns⁷ of 1936 and 1938. The coordinates are displayed in WGS84 / UTM zone 33N. (b) We divided the images into 17 groups with convergent camera geometries for SfM reconstruction in Agisoft Metashape (Extended Data Fig. 4). We provide the Svalbard-wide (c) 1936 orthophotomosaic, (d) 1936 digital elevation model (DEM), and (e) 1936-2010 elevation change (∆h) at 20 m and 50 m resolution. We also provide the 1936-2010 ∆h datasets at 5 m resolution, although, because of file size constraints, these data are divided into 8 files for each of the Svalbard zones depicted in Fig. 2d. The unprocessed point clouds from the 17 regional SfM reconstructions in (c) are available as .laz files. In addition to the raster datasets in (c-e), we provide a .shp file inventorying the 1936 extents of Svalbard glaciers and a spreadsheet recording statistics such as ∆h/∆t, ∆M/∆t, DEM uncertainty, and NORA10 climate fields⁵ (mean summer temperature, precipitation as snow, etc.). See Data availability.