The use of airborne hyper-spectral remote sensing for mapping water bodies in the Cape Flats area of Cape Town, South Africa

Abstract

A hyper-spectral airborne campaign was conducted in August 2005 in Cape Town, South Africa to map water constituents as chlorophyll a (Chl) and total suspended solids (TSS) in two relatively small inland water bodies. The sensor employed in this campaign was the AISA-ES, a hyper-spectral airborne imager with a spectral range spanning from 400 to 2370 nm. Ground-truthing was carried out simultaneously with the flights over the water bodies; water samples were taken from various locations in both bodies of water for laboratory analysis. Reflectance spectra were used for the estimation of -Chl and TSS concentrations, which ranged from 7 to 45 mg L-1 for TSS and from 5 to 245 μg L-1 for Chl. The optical information was used for construction of quantitative thematic maps of the spatial distribution of these water constituents. This work demonstrates the suitability of hyper-spectral airborne technology for mapping the concentrations of water constituents in relatively small water bodies.