Thesis subject

MSc thesis topic: Inventory stem map alignment based on T-LiDAR based map

Light detection and ranging (LiDAR) has been proposed as a suitable technique for mapping forest. A number of parameters can be derived from these 3D maps such as tree height, diameter at breast height (DBH), and even tree volume providing an objective, practical and cost-effective solution for forest inventories.

LiDAR can be operated in airborne configuration (Airborne laser scanning (ALS) or in a terrestrial setup (TLS). TLS measures forests from below canopy and offers a much more detailed description of the individual trees and stands. In addition to this, traditional forest inventory also provide complement information about the forest, however, some measurements are subject to the instrument’s accuracy and the expert’s experience. These factors create uncertainty over the measured value. TLS can provide another, more detailed, value, which can improve the inventory.

The aim of this research is to derive an algorithm to align stems from forest inventory to stem maps from terrestrial LiDAR data in the context of an international project run by CIFOR and Wageningen University.

For this purpose, TLS data were acquired during 2013 and 2014 in sustainable logging forest plots in three countries, Peru, Indonesia and Guyana. A total of 29 plots of 30x40m with a scans from 8 to 13 scans per plot were acquired. Pre-processing has been done on each plot and data is ready to be analysed. Each plot has a forest inventory for all species with DBH >10cm. Data such as tree height, DBH, crown size, specie and height at first branch was measured.

Objectives and Research questions

  • How to process TLS data to create DBH maps.
  • Determine the accuracy of inventory map compared to DBH map for trees with DBH >20cm

Expected reading list before starting the thesis research

  • Simonse, M., Aschoff, T., Spiecker, H., & Thies, M. (2003, September). Automatic determination of forest inventory parameters using terrestrial laser scanning. In Proceedings of the scandlaser scientific workshop on airborne laser scanning of forests (Vol. 2003, pp. 252-258).
  • Bienert, A., Maas, H. G., & Scheller, S. (2006, February). Analysis of the information content of terrestrial laserscanner point clouds for the automatic determination of forest inventory parameters. In Workshop on 3D Remote Sensing in Forestry (Vol. 14, p. 15th).

Theme(s): Modelling & visualisation