We present an analytical description of a magnetization reversal phase diagram of ferromagnetic thin films that have uniaxial perpendicular anisotropy. The phase equilibrium lines were calculated from a micromagnetic consideration of equilibrium conditions of the wall motion, dendritic growth, and nucleation processes. The phase diagram characterizes well simulated domain evolution patterns: typical domain evolution patterns are predicted accurately in the corresponding phases accompanied by gradual phase transitions across the phase equilibrium lines. (C) 2002 American Institute of Physics.