University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Christina Glas
(2017):
Auswertung von multitemporaler hyper- bzw. multispektraler Fernerkundungsdaten zur Erkennung von Vitalitätsveränderungen an Fichten.
Master / Diploma Thesis - Institut für Vermessung, Fernerkundung und Landinformation (IVFL),
BOKU-Universität für Bodenkultur,
pp 93.
UB BOKU
obvsg
- Abstract:
- Due to higher temperatures and less precipitation, bark beetle infestations occur more often in Norway spruce. Nowadays the search of indicators for these attacks is conducted manually, but this practice is cost and time intensive. The aim of this thesis is to invent an alternative method to assess the vitality of trees. Therefore, a remote sensing approach was tested. To analyse the change of health status two study areas in Bavaria, Germany were chosen. The main difference between the test sites is the age of the trees. Half of the trees got a treatment (ring-barking) which should simulate a bark beetle attack. To monitor the vitality of the trees two different types of remote sensed data were acquired. On the one hand hyperspectral airborne data (HySpex) and on the other hand multispectral satellite data from the WorldView-2 satellite (WV2) were used. The spatial resolution of the HySpex data is 0.5m and it covers the spectral range from 415 to 2500nm. Compared to the HySpex data the WV2 data is cheaper but the spectral resolution is coarser. The spatial resolution is 0.5 m after pan-sharpening was conducted. The first step of the analysis was to look at the spectral signatures and their derivations. Afterwards vegetation indices and similarity measures were calculated. Additionally, the Red Edge Inflection Point and angle indices were analysed with the HySpex data. Finally, a classification algorithm (Random Forest) was applied. In June 2014 a coarse separation was possible in the older stock. This late occurrence of separation was also observed with the vegetation and angle indices and the RF. The WV2 analysis achieved even worse results. The vitality of the trees was nearly not affected by ring-barking at the younger test site. Hardly any vegetation or angle indices (HySpex) showed significant differences between the groups. In comparison, the WV2 results were even worse than those of the HySpex data.
- Beurteilende(r): Atzberger Clement
- 1.Mitwirkender: Immitzer Markus