3D pointclouds and orthophotos derived from historical aerial images are important sources for quantifying landscape changes used by various resaerchers (e.g. Glaciologists, Geomorphologists, Hydrologists, Botanists). Within the SEHAG project, funded by fhe FWF, we derived several historical snapshots for selected study areas in Austria and Italy. This dataset contains a pointcloud (1_Pointcloud), digital surface model (2_DSM) and orthophoto (3_OP) of the Kaunertal (Austria) derived from historical nadir images from 1953 and 1954 (originial image data (c) 1953/54 BEV and Land Tirol). The photogrammetric processing (i.e. orientation, 3D reconstruction) was done in Match-AT. All raster products (e.g. OP, DSM) were derived using OPALS. The OP has a resolution of 0.5m x 0.5m and the DSM a resolution of 2.5m x 2.5m. 

Coordinate system and projection: UTM 32N (EPSG:25832) with ellipsoidal heights (ETRS89/GRS80)

1_Pointcloud:

HT_5354_v2.las: Original pointcloud from the featured based matching of the nadir images.

HT_5354_v2_pdens1.tif: Density of the feature based points per square meter. Low density regions corresponds to areas with poor image texture (e.g. shadow, snow). 

2_DSM:

HT_5354_v2.tif: Interpolated surface model with a grid size of 2.5m. Moving planes interpolation using the 8 nearest neighbours and a maximum search radius of 16m. Holes were filled through triangular meshing.

HT_5354_v2_shd.tif: Shading of the interpolated surface model. 

HT_5354_v2_sigma0map.tif: Variance of the 8 points from the best fitting plane per grid point. 

3_OP: Orthophoto with a pixel size of 50cm. 

4_QLT: 

HT_5354_v2_dif2ref_zco_1m.tif: Colour coded differences to the used reference surface model. HT_5354_v2_dif2ref_zco_1mLegend.svg