Evaluation of SPOT HRV Data in Mapping Mangrove Forests in a Temperate Zone

Abstract

Mangrove forests in the western Waitemata Harbour, Auckland, New Zealand were mapped as lush and stunted, in conjunction with eight other categories of cover, from winter and summer SPOT multispectral (XS) data individually, and jointly with a panchromatic (PAN) band. After the mangrove-containing coastal zone was geographically stratified, the sub‐scene data was classified using the maximum likelihood method. Lush mangroves are mapped 77.5 % and 82.7 % correctly from the XS data alone. The accuracy levels for stunted mangroves are lower at 67.5 % and 60% correct. These accuracy levels rise to 82.5 % for the winter image and 78.8 % for the summer image if the misclassifications between the two classes of mangroves are disregarded. Incorporation of the PAN band in the classification of the winter image increased the accuracy by 2.5 % for lush mangroves and by 12.5 % for stunted mangroves. Thus, SPOT HRV data can generate mangrove maps accurately in a temperate zone. The PAN band is effective in improving the mapping accuracy for stunted mangroves, but less so for dense mangroves due to the similarity of its spectral content to that of the first two XS bands.