CGRG Bibliography of Canadian Geomorphology
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Author : Adam, S.; Wiebe, J.; Collins, M.; and Pietroniro, A.
Date : 1998
Title : Radarsat flood mapping in the Peace-Athabasca Delta, Canada
Publication : Canadian Journal of Remote Sensing
Issue : 24(1):
Page(s) : 69-79
Abstract
Synthetic Aperture Radar imagery has proven very useful for mapping flooded areas due to the sensitivity of microwaves to liquid water. Spring flooding during May 1996 and May 1997 in the Peace-Athabasca Delta, Canada is successfully mapped using calibrated RADARSAT imagery. We have identified flood water distribution by segmenting the images into three distinct classes: open water, flooded willow, and non-flooded areas. Supervised classification results of the original images are not acceptable due to the large local variance introduced by speckle. To improve the classification results we utilise image tone and texture. Initially, speckle is minimised with a 7x7 Gamma MAP (Maximum A Posteriori) filter applied to each image. The resulting classifications are signficantly improved with a Kappa coefficient of over 90%. Textural information is further added to the classification, via a coefficient of variation scene. With this additional information Kappa is slightly reduced, however, visual inspection shows that some channel and lake edges are more accurately classified as flooded willows. These areas represent vegetation transition zones and offer excellent habitat for water fowl. Although the three main classes have distinct textural and tonal signatures, mean properties (i.e. image tone) of the speckle reduced images are sufficient for an accurate classification.
Bibliography of Canadian Geomorphology