Switching properties of a regular square lattice of 40x40x3 mu m(3) highly uniaxial, single domain magnetic garnet pixels have been measured magnetooptically. ''Up'' and ''down'' switching fields, coercivities and interaction fields were measured on an assembly of hundreds of particles, Statistical analysis of the data shows the relationship between major loop parameters and mean values of the distributions, Local demagnetizing tensor elements were calculated for the non-ellipsoidal geometry and the interaction fields from different neighbors were computed. The importance of the effect of the geometry, shape and size of particles on the switching properties is demonstrated, The agreement with experimental values is very good. The simplicity of this model system iu attractive for studying artificially structured 2-D arrays of small particles.