Madonsela, SabeloCho, Moses AMathieu, Renaud SAMutanga, ORamoelo, AbelKaszta, ZVan De Kerchove, RWolff, E2018-03-092018-03-092017-06Madonsela, S. et al. 2017. Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species. International Journal of Applied Earth Observation and Geoinformation, vol. 58: 65-730303-24341569-8432https://www.sciencedirect.com/science/article/pii/S0303243417300181doi.org/10.1016/j.jag.2017.01.018http://hdl.handle.net/10204/10092Copyright: 2017 Elsevier. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website.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.enTree species discriminationConservationSavannahWorldView-2PhenologyYellow bandArticleMadonsela, S., Cho, M. A., Mathieu, R. S., Mutanga, O., Ramoelo, A., Kaszta, Z., ... Wolff, E. (2017). Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species. http://hdl.handle.net/10204/10092Madonsela, Sabelo, Moses A Cho, Renaud SA Mathieu, O Mutanga, Abel Ramoelo, Z Kaszta, R Van De Kerchove, and E Wolff "Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species." (2017) http://hdl.handle.net/10204/10092Madonsela S, Cho MA, Mathieu RS, Mutanga O, Ramoelo A, Kaszta Z, et al. Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species. 2017; http://hdl.handle.net/10204/10092.TY - Article AU - Madonsela, Sabelo AU - Cho, Moses A AU - Mathieu, Renaud SA AU - Mutanga, O AU - Ramoelo, Abel AU - Kaszta, Z AU - Van De Kerchove, R AU - Wolff, E AB - 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. DA - 2017-06 DB - ResearchSpace DP - CSIR KW - Tree species discrimination KW - Conservation KW - Savannah KW - WorldView-2 KW - Phenology KW - Yellow band LK - https://researchspace.csir.co.za PY - 2017 SM - 0303-2434 SM - 1569-8432 T1 - Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species TI - Multi-phenology WorldView-2 imagery improves remote sensing of savannah tree species UR - http://hdl.handle.net/10204/10092 ER -