In this study, we evaluated the level of diversity of street facades using Simpson's diversity index, a measure of diversity frequently utilized in the field of ecology. The following results are provided. (1) We extracted two types of street facades: one represented a type of diversity, where in the composition ratio of each color was almost even for the entire street facade; the other represented a type of unity, such that the dominant material accounted for more than 39% of the composition

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... tio within the street facade. (2) The physical and psychological values of diversity indicate a correlation. Consequently, the method results indicate that in order to increase the attractiveness of streetscapes, it is important to recognize a dominant color or material of each street facade.