LIDAR AND LANDSAT BASED MAPPING OF PEATLAND AND PERMAFROST TERRAIN USING OBJECT-BASED CLASSIFICATION, NORTHEAST ALBERTA

Approximately 210,000 km²of Northern Alberta exists within the zone of sporadic discontinuous permafrost, with 26% of the peatlands being estimated to contain perennially frozen ground. Two landform types are associated with permafrost peatlands in Alberta: forest-covered palsa bogs and larger peat plateaus, which form part of a heterogeneous mosaic of uplands, swamps, bogs and fens. The influence of permafrost on ground stability, ecology and surface hydrology, and its sensitivity to disturbance by infrastructure development, makes it an important component of land use and reclamation planning. However, to date, there has been limited mapping at a scale sufficient for these purposes, with previous airphoto-based interpretations providing only a small-scale delineation of the forest-covered permafrost terrain. This research presents results from a methodology and study situated near Fort McMurray, northeast Alberta. The aim of the study was to test the applicability of multispectral (Landsat, SPOT) and LiDAR-derived terrain morphological attributes to classify peatland and permafrost terrain using pixel and object-based image analysis (OBIA) approaches. Multi-resolution segmentation of LiDAR and multispectral data is used to delineate terrain objects. An attribute selection approach is then applied to determine the effectiveness of different spectral and spatial metrics, which are subsequently classified using random forests into upland, peatland, permafrost, and thermokarst terrain classes. Accuracy assessment has demonstrated high classification accuracies (>85%), but when contrasted with pixel-based classification, the OBIA approach produced more spatially coherent results concerning the distribution of localized palsa bogs. These results also demonstrate that near-surface permafrost is significantly more extensive than previously identified in northern Alberta, even at relatively low latitudes (~56.5°).