Matlab code used to compute the capacitance matrix for a collection of spherical particles, which can have arbitrary positions in three-dimensional space. A multipole expansion is used, in terms of a basis consisting of spherical harmonics. After generating the capacitance matrix with the routine MakeC_mn.m, the eigenvectors are computed. Then, the landscape and the upper landscape, as defined in the reference [Landscape of wave localisation at low frequencies, Davies & Lou, 2023], are computed. The code can be executed by running the file RUN_example.m in Matlab, which distributes 15 unit spheres on the z=0 plane, as a demonstrative example.