Particle shape analyzer Partisan - An open source tool for multi-standard two-dimensional particle morphometry analysis

Abstract

Volcanic particles are commonly characterized using 2D morphometric analysis. Results of analysis are used to compare particles from different events or phases, and to infer clast-generating mechanisms, eruptive styles and the aerodynamic behavior of particles. Such particle- shape analyses can be made from images of particle silhouettes or cross-sectional slices. A number of different morphometric systems have been used to date, with each using its own nomenclature and mathematical definitions of shape-describing parameters. Some of the parameters can only be obtained using specific commercial software. With the PARTIcle Shape ANalyzer PARTISAN we present a freeware tool which parameterizes 2D shapes and provides a suite of shape parameters, following the different standards of the five most commonly used 2D morphometric systems. PARTISAN enables the user to study and archive the results of particle-shape analysis in a format compatible with various published routines, thus increasing the potential for linking new work with results of work previously published by other groups. It will also allow cross-comparison of results obtained by different morphological routines. We see PARTISAN as a “Rosetta Stone” for volcanological particle morphometry, and it opens the way for development of widely agreed treatment of particle shapes in 2D.