Pan3D - Nationwide 3D data from historical aerial imagery

Knowledge of tree resources and the structure of forests is key for managing various forest functions and services. Information on the third dimension (z component) has become more and more important over the last decade.

Surface models provide key knowledge of the vertical structure of forests. Aerial stereo imagery acquired during routine mapping campaigns covering the whole of Switzerland (41,285 km²), offers a potential data source to calculate digital surface models (DSMs). These DSMs in combination with an existing digital terrain model (DTM) can then be used to derive vegetation height models (VHM). For the recent past years a country-wide, high-resolution DSM and VHM could successfully be processed from digital ADS40/80 imagery (Ginzler and Hobi, 2015). These datasets open up new possibilities for biomass estimations, forest structure analysis and biodiversity assessment.

In this project we use historical, panchromatic frame images, which were digitized in the framework of the Swiss Land Use/Cover statistics, to generate high resolution DSMs for the two periods 1979-1985 and 1990-1997. With a highly automated workflow we are able to process country-wide VHMs which extends the time series of information about forest structure in Switzerland and thus opens up a whole range of new research possibilities connected to past and current forest structure information.