WETLAND MAPPING IN NEW BRUNSWICK, CANADA WITH LANDSAT5-TM, ALOS-PALSAR, AND RADARSAT-2 IMAGERY

Abstract

Several maps of wetland areas in central New Brunswick, Canada, were produced by applying the Random Forests classifier to different combinations of optical Landsat-5 TM images, dual-polarized (HH, HV) Radarsat-2 C-band and Alos-1 PalSAR L-band Synthetic Aperture Radar (SAR) images and digital elevation data. The resulting maps were compared to 199 GPS wetland sites that were visited between 2012 and 2018 as well as to a combination of two wetland maps currently used by the Province of New Brunswick. The number of correctly identified GPS wetland sites was the highest when both the Alos-PalSAR and Radarsat-2 images are used (97.9%). This percentage of correctly identified sites were well above the accuracy of the official New Brunswick wetland maps (44.7 %). With the best-classified image, the misidentifications were due to wetlands not being classified in the right wetland class, and just one case was a wetland site being classified in a non-wetland class. For the NB wetland map, about a quarter of the wetland validation sites were classified in a non-wetland class, and about the same number of sites were classified in the wrong wetland class.