Ryuji Takaki1 and Nobutaka Ueda2
1Kobe Design University, Nishi-ku, Kobe, Hyogo 651-2196, Japan
2Hiroshima-Gakuin, Nishi-ku, Hiroshima, Hiroshima 733-0875, Japan
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(Received November 3, 2006; Accepted August 10, 2007)
Keywords: Spiral, Curvature, Logarithmic Spiral, Archimedean Spiral, Vortex
Abstract. A method is proposed to characterize and classify shapes of plane spirals, and it is applied to some spiral patterns from historical monuments and vortices observed in an experiment. The method is based on a relation between the length variable along a curve and the radius of its local curvature. Examples treated in this paper seem to be classified into four types, i.e. those of the Archimedean spiral, the logarithmic spiral, the elliptic vortex and the hyperbolic spiral.