This study, conducted to support for urban thermal environment planning, developed a new method for mapping the spatial structure of urban canopy layers. The technique, called Raster-Patch-Cluster Scheme, employs landscape and ecological indicators combined with thermal characteristics identified by use of thermal satellite images. It was found that the urban thermal environment develops at the local scale and exhibits differences in density and forms of canopy layers. ASTER/TIR with 90 m resolution was found to be a useful data source for elucidating such local climatic phenomena. The intensities of local heat or cool islands exhibit significant logarithmic relationships with the size of urban canopy features. This means that the extent and intensity of urban heat islands increases with the expansion of urbanized areas of a city as well as with the agglomeration of land use intensity. The conclusions suggest that mitigation measures for the prevention of urban island development are likely to be effective if implemented at early stages of urbanization.