The aerial images for the entire Austrian federal territory are updated in a three-year cycle, with around one third of the national territory being reflown each year. These aerial surveys are commissioned as part of a federal-state cooperation and are primarily used to create two-dimensional orthophotos (rectified, true-to-scale aerial images) for a variety of applications. The original aerial images are recorded with a transverse and longitudinal overlap, which makes it possible to generate high-resolution, three-dimensional data (point clouds, meshes, surface models) of the earth's surface using the image matching method, from the results of which central spatial information - such as vegetation heights, vegetation structures, terrain changes and building heights - can be derived, which provides a valuable basis for numerous application and research projects. At the moment, the calculation of one third of the national territory takes about one year of computing time and is currently being carried out at the Federal Office of Metrology and Surveying (BEV) - optimized for urban areas - and at the Federal Research Centre for Forests (BFW) - optimized for forest areas (forest inventory). The image matching products created to date are carried out on stand-alone computers and are only available after a long delay. The contracted flight companies supply aerial image data on hard disks, generating around 150 terabytes of data per year.
Objective
The acceleration of the process for creating high-resolution digital surface models and the development of the infrastructure were successfully completed. The cooperation partners were involved in the development and evaluation of our calculation method at exchange meetings. The workflow and processing parameters were optimised in order to be able to generate prompt results with comparable quality (maximum quality with an automated process, without post-processing). To this end, the parameters for creating the surface models were optimised and the results tested (comparison with existing products and elevation data). Tests were also carried out to calculate point clouds and mesh models. A central aerial image repository was set up (currently planned utilisation period of 5 years). The ICT infrastructure for LTFS long-term archiving was procured and integrated into the existing system architecture.
Work 2025
The cooperation with the Federal Office of Metrology and Surveying (BEV) and the Federal Forest Research Centre (BFW) to exchange experiences and further develop the methods will be continued. The results and findings of the project will be published in a final report and presented at the GIS-Jour-Fixe. A concept for the long-term archiving of the raw aerial image data on LTO tapes will be developed and the archiving of the original aerial images obtained to date will be started. Increased effort is to be expected due to the large number of data carriers of older flight blocks and older, possibly defective hard discs. The management of the original aerial image data carriers will be transferred to the library system. The ongoing transfer of new flight blocks to the aerial image storage and their transfer to the BAB library and long-term archiving will be transferred to the regular operation of the BAB.
Schedule
Project start: 01/2021
Project end: 12/2025
