Spectral analysis of building materials used in Japan

To conduct appropriate urban planning for a given area, understanding latent urban problems such as excessive concentration of population, aging of residents, and grasping temporal changes in both societal and physical structures in the area are important. In this study, as a basis for the development of the descriptive indices for urban characteristics, we discuss the applicability of remote sensing techniques to classify urban surface materials commonly used in Japan, based on an analysis of spectral reflectance data, ranging from 350 nm to 2500nm, of various rooftop and road pavement materials, which were collected for this study with a field spectrometer. The building materials collected in the field measurement were a set of roof top materials including Japanese roof tiles, tin sheets, natural and artificial roofing slates, waterproof sheets, as well as a set of road pavement materials including asphalt surfaces, pervious pavement tiles, with various colors, set in an outdoor experiment field simulating urban land use. In the field measurement, some of the materials were measured under multiple solar conditions by changing solar incident angles and sensor directions so that the influence of observation conditions could be analyzed. The results of the spectral analysis suggest that many roofing materials studied in this paper showed relatively similar reflectance patterns in visible part of the spectrum. Those materials, however, displayed noticeable differences from one another in the spectral responses in the infrared range. Regarding the road pavement materials, distinctive spectral characteristics were observed also in the infrared range.