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International Institute for Geo-Information Science and Earth Observation (ITC) 2015

Mapping of vegetation types and bush encroachment in Namibia

Ruiz Beltrán, A.P.

Titre : Mapping of vegetation types and bush encroachment in Namibia

Auteur : Ruiz Beltrán, A.P.

Etablissement de soutenance : University of Twente International Institute for Geo-Information Science and Earth Observation (ITC)

Grade : Master of Science in Geo-Information Science and Earth Observation 2015

Résumé
This thesis deals with vegetation types and bush encroachment in Namibia. Vegetation types are groups of plants that grow together in a certain area. Bush encroachment is the process where a grass- dominated ecosystem transforms into a tree- dominated ecosystem. The first objective of this thesis was to map the vegetation types in Namibia using SPOT VGT NDVI data of 15 years. The classification of the SPOT GVT NDVI data of 15 years was carried out using the Iterative Self- Organized unsupervised clustering algorithm (ISODATA). Based on separability statistics the number of optimum clusters was selected as 73. Based on the NDVI statistics of each cluster and environmental parameters, vegetation types were inter preted, reducing the number of clusters to 20 classes. SPOT- VGT NDVI time series from 15 years can be used to map vegetation types at a national level. The second objective was to explore the possibility to detect bush encroachment in Namibia with SPOT VGT NDVI time series profiles. As a proxy for ground observations historical (2002 – 2004) and recent Google Earth images were analyzed to assess changes in bush density and canopy cover, however, these changes were not detected.

Version intégrale (ITC)

Page publiée le 1er février 2018