Improved AHN3 Gridded DTM/DSM

Improved AHN3 Gridded DTM/DSM

Alhoz, Khaled (TU Delft Architecture and the Built Environment)
Kenesei, Kristof (TU Delft Architecture and the Built Environment)
Papageorgiou, Manos (TU Delft Architecture and the Built Environment)
Keurentjes, Lisa (TU Delft Architecture and the Built Environment)
de Jong, Maarten (TU Delft Architecture and the Built Environment)

Ledoux, H. (mentor)
Peters, R.Y. (mentor)

Delft University of Technology

Geomatics

Synthesis Project 2020

2020-06

The outcome of the project has been successful from the interpolation perspective, where the final results have shown major improvements over the original rasters, and a multitude of possible other interpolation methods have shown potential. In the end, the algorithm used to create the gridded DTM was
based on Startin’s Laplace interpolation and for DSM a Python implementation of quadrant-based IDW was used. The Startin Laplace method gives statistically good results while running quickly on it’s Rust base, though using quite some memory. The quadrant-based IDW has proven to be the best way to interpolate results which include the buildings, creating crisp edges without too many artefacts. Fur-
thermore, the introduction of a polygon water flattening step was essential to prevent no-data values where water bodies prevented for accurate interpolation. The long-shot goal of being able to process all the tiles for the Netherlands was missed by a lot, eventually choosing to interpolate a series of tiles neighboring Delft to create a contiguous result set. Zuid-Holland has therefore only been partially completed, whereas the expectation was to be able to complete this area with ease in three days. An initial overview of the comparison for a single tile in Rotterdam (37HN1), can be seen in Figure 1.3 for the DTM results and Figure 1.4 for the DSM results.

DTM/DSM
scaling
Interpolation
Hydro-Flattening
Hole Filling
Ground Filtering

http://resolver.tudelft.nl/uuid:153b2a82-05ba-412b-8a0a-119cb5689afd

GitHub repository of the algorithms used for DTM/DSM generation (with documentation): https://github.com/tudelft3d/geo1101.2020.ahn3

Student theses

student report

© 2020 Khaled Alhoz, Kristof Kenesei, Manos Papageorgiou, Lisa Keurentjes, Maarten de Jong