Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species

Show simple item record Madonsela, Sabelo Cho, Moses Azong Mathieu, Renaud Mutanga, Onisimo Ramoelo, Abel Kaszta, Zaneta Van de Kerchove, Ruben Wolff, Eléonore 2017-05-24T07:40:04Z 2017-06 en
dc.description.abstract Biodiversity mapping in African savannah is important for monitoring changes and ensuring sustainable use of ecosystem resources. Biodiversity mapping can benefit from multi-spectral instruments such as WorldView-2 with very high spatial resolution and a spectral configuration encompassing important spectral regions not previously available for vegetation mapping. This study investigated i) the benefits of the eight-band WorldView-2 (WV-2) spectral configuration for discriminating tree species in Southern African savannah and ii) if multiple-images acquired at key points of the typical phenological development of savannahs (peak productivity, transition to senescence) improve on tree species classifications. We first assessed the discriminatory power of WV-2 bands using interspecies-Spectral Angle Mapper (SAM) via Band Add-On procedure and tested the spectral capability of WorldView-2 against simulated IKONOS for tree species classification. The results from interspecies-SAM procedure identified the yellow and red bands as the most statistically significant bands (p = 0.000251 and p = 0.000039 respectively) in the discriminatory power of WV-2 during the transition from wet to dry season (April). Using Random Forest classifier, the classification scenarios investigated showed that i) the 8-bands of the WV-2 sensor achieved higher classification accuracy for the April date (transition from wet to dry season, senescence) compared to the March date (peak productivity season) ii) the WV-2 spectral configuration systematically outperformed the IKONOS sensor spectral configuration and iii) the multi-temporal approach (March and April combined) improved the discrimination of tress species and produced the highest overall accuracy results at 80.4%. Consistent with the interspecies-SAM procedure, the yellow (605 nm) band also showed a statistically significant contribution in the improved classification accuracy from WV-2. These results highlight the mapping opportunities presented by WV-2 data for monitoring the distribution status of e.g. species often harvested by local communities (e.g. Sclerocharya birrea), encroaching species, or species-specific tree losses induced by elephants. en_ZA
dc.description.department Geography, Geoinformatics and Meteorology en
dc.description.embargo 2018-06-30
dc.description.sponsorship The Belgian Science Policy Office (BELSPO)/Research Programme for Earth Observation STEREO II (contract N° SR/11/153) project GRAZEO "Grazing suitability indicators from Earth Observation to improve buffalo-cattle contact risk models" as well as the South Africa's National Research Foundation (NRF) and the Applied Center for Climate and Earth Science Systems (ACCESS). en
dc.description.uri en
dc.identifier.citation Madonsela, S., Cho, M.A., Mathieu, R., Mutanga, O., Ramoelo, A., Kaszta, Z., Van de Kerchove, R. & Wolff, E. 2017, 'Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species', International Journal of Applied Earth Observation and Geoinformation, vol. 58, pp. 65-73. en
dc.identifier.issn 1872-826X (online) en
dc.identifier.issn 1569-8432 (print) en
dc.identifier.other 10.1016/j.jag.2017.01.018 en
dc.language.iso English en
dc.publisher Elsevier en
dc.rights © 2017 Elsevier B.V. All rights reserved. Notice : this is the author's version of a work that was accepted for publication inInternational Journal of Applied Earth Observation and Geoinformation. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in International Journal of Applied Earth Observation and Geoinformation, vol.58, pp. 65-73, 2017. doi : 10.1016/j.jag.2017.01.018. en
dc.subject Tree species discrimination en
dc.subject Conservation en
dc.subject Savannah en
dc.subject WorldView-2 (WV-2) en
dc.subject Phenology en
dc.subject Yellow band en
dc.title Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species en
dc.type Postprint Article en

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