Validation of the sigmoid wave curve fitting algorithm on a forest-tundra ecotone in the Northwest Territories, Canada

Article history: Received 25 August 2008 Received in revised form 22 November 2008 Accepted 26 November 2008 Ecotones are gradual transitions between two adjacent ecological systems. Ecotones are characterized by their spatial properties which are reflected in an ecotone width and location and the temporal variation across time during succession or environmental change on both a local and a global scale. If only one main environmental factor drives this gradual change the shape of the ecotone is evident as a sigmoid wave. In this paper we explore a two-dimensional sigmoid wave curve fitting algorithm that describes an ecotone and validate it on classified remote sensing data of a forest-tundra ecotone in the Northwest Territories of Canada. The estimated location and width of the forest-tundra ecotone are validated with digital land cover data. We conclude that the algorithm was able to delineate the forest-tundra ecotone based upon the classified remote sensing image and is robust for various algorithm parameter settings. © 2008 Elsevier B.V. All rights reserved.