Miller circularity index

Compute Miller circularity index of polygons.

Usage

mafa_circularity(sfpolygons)

Arguments

sfpolygons

sf object composed of polygons.

Value

sfpoygons with index result in a new column, named miller_index.

Details

\(I_M = \frac{4\pi A_p}{P_p^2}\), with \(A_p\) the area of a polygon and \(P_{p}\) its perimeter. Miller circularity index is the ratio between the area of the polygon and a theoretical circle with the same perimeter. In this sense, the index is also written as a similarity index to a circle \(I_M = \frac{A_p}{\pi(\frac{P_p}{2\pi})^2}\). Miller index is normalized between [0-1].

References

Robert, Sandrine, Éric Grosso, Pascal Chareille, et Hélène Noizet. 2014. « MorphAL (Morphological Analysis) : un outil d’analyse de morphologie urbaine ». In Archéologie de l’espace urbain, édité par Elisabeth Lorans et Xavier Rodier, 451‑63. Perspectives Villes et Territoires. Tours: Presses universitaires François-Rabelais. https://doi.org/10.4000/books.pufr.7717.