Towards a strategy to implement the Canadian Wetland Inventory using satellite remote sensing

This review describes the context of the Canadian Wetland Inventory (CWI) and then defines the specifications, establishes the most appropriate dataset, and explores the options for its implementation. The CWI is based on the assumption that a consistent map for all areas of Canada using satellite imagery can be produced for a minimum mapping unit of 1 ha. The CWI will establish the state of land cover for wetlands around year 2000, and the CWI map will classify wetlands according to the following scheme defined in the Canadian Wetland Classification System: bog, fen, marsh, swamp, and shallow water. It will then be possible to roll the map up into simpler classes (i.e., upland, wetland, open waters, and coastal waters) compatible with other map products. A wide array of datasets is available, and their potential use in the context of the CWI is explored. The best options regarding the mapping method and the evaluation of the map products are both described, keeping in mind that the most suitable method must strike a balance between methodological advances and practical considerations. This review places the various limitations associated with the CWI in perspective and supports several of the CWI specifications; it should also facilitate selection of a strategy tailored to its implementation, in particular for the classification method and the evaluation of the map.