This paper applies different methodologies through measurement and simulation for the partial shading analysis of solar photovoltaic (SPV) arrays. A two-diode photovoltaic solar cell model evaluates SPV arrays under shading conditions. Experimental data from two identical 1.5 kWp PV generators were used as a study case. One is subjected to shading caused by the branches of a tree, resulting in its electricity production being affected for several days, and the other is shadow-free. The authors use a methodology based on short circuit of the solar cells to determine the different irradiance levels. It was considered because it avoids using several irradiance sensors to map the shaded and unshaded regions in a shadow SPV array. The two-diode photovoltaic solar cell model used was developed in matlab/simulink. The applied model and the map irradiance methodology can be used to represent current–voltage (IV) curves in complex shading. For example, what could help identify if a given SPV array is working on a global maximum power point or a local maximum power point. Furthermore, the experimental results demonstrated that the model and methodology are useful in understanding what happens with SPV arrays in very complex shadow situations.