Subpixel classification of alder trees using multitemporal LANDSAT Thematic Mapper imagery

Abstract

An unmixing method was used to estimate the area of alder trees from multitemporal Thematic Mapper (TM) imagery.of the Kushiro mire, an important wetland area in Japan. Because the spectral radiance (endmember) of alder coverage within a pixel must be precisely known before the unmixing method is applied, we first collected ground truth data for the canopy area of alder using field survey methods, and aerial photographs. The alder endmember was calculated by linking TM imagery and the ground truth data. Alder coverage was estimated more precisely than it was with classification by the maximum-likelihood method. Furthermore, the alder area could be evaluated within a pixel, which cannot be classified as alder by the maximumlikelihood method.