  A common challenge in scientific and technical domains is the quantitative
description of geometries and shapes, e.g. in the analysis of microscope
imagery or astronomical observation data. Frequently, it is desirable to go
beyond scalar shape metrics such as porosity and surface to volume ratios
because the samples are anisotropic or because direction-dependent quantities
such as conductances or elasticity are of interest. Minkowski Tensors are a
systematic family of versatile and robust higher-order shape descriptors that
allow for shape characterization of arbitrary order and promise a path to
systematic structure-function relationships for direction-dependent properties.
Papaya2 is a software to calculate 2D higher-order shape metrics with a library
interface, support for Irreducible Minkowski Tensors and interpolated marching
squares. Extensions to Matlab, JavaScript and Python are provided as well.
While the tensor of inertia is computed by many tools, we are not aware of
other open-source software which provides higher-rank shape characterization in
2D.
