Numerical micromagnetic simulations are performed to study the magnetic configurations of ultrathin films with spatially varying magnetic anisotropy. Investigating infinitely long stripes with alternating in-plane/out-of-plane uniaxial anisotropy we find states of uniform, canted and alternating magnetization as function of the width of the stripes. A simple analytical model is given to describe the canting by means of a fourth order anisotropy term that is caused solely by the microstructure. Furthermore, the system is described macroscopically by averaging the magnetization of the various states. In this framework the spin reorientation transition between states of uniform magnetization is studied as a function of the stripes density. We find that the rotation of the average magnetization takes place always continuously and is sharper for a higher density of stripes.