Spectral angle mapper algorithm for mangrove biodiversity mapping in Semarang, Indonesia
Monitoring biodiversity is a key component of sustainability research related to safeguarding ecosystems. Although there still exist limits to its application, remote sensing has been used to map mangrove biodiversity and its distribution using spectral reflectance. This study considers the mangrove ecosystem in the Semarang coastal area using the Spectral Angle Mapper (SAM) method for biodiversity identification at species level. The remote sensing data is SPOT 7 imagery, acquired on 24 December 2019. In situ spectral reflection measurements were performed using a USB4000 spectrometer. The result from in situ measurement is referred to as the spectral library used for mangrove classification. Eight mangrove species were identified by the SAM method in this study, with a preponderance of the species Avicennia marina in the northern part of the study area, an open area that directly faces the sea, corresponding to the original habitat of Avicennia marina. The study shows that while the SAM method can be considered accurate for species with larger concentrations, the classification results demonstrate an overall moderate-low accuracy of 52% because some species classes have small patches that are intermingled with areas of different land-use. Further developments in remote sensing analysis techniques and more research will be necessary to endeavor to overcome these limits.