inorganic chemistry - Why does ozone have an electrostatic potential map similar to that of SO2?

This is the electrostatic potential for ozone.

This is the electrostatic potential for sulfur dioxide.

_{(Click to enlarge)}

They look almost exactly the same except one is all oxygen atoms and the other has sulfur in the center instead of oxygen.

Why does ozone have an MEP (molecular electrostatic potential) similar to that of SO2?

Answer

Resonance structures of $\ce{SO2}$ and $\ce{O3}$.

As you can see from the diagram $\ce{O3}$ and $\ce{SO2}$ are isoelectric and have the same shape and this accounts for their very similar electrostatic potential maps. Both molecules are polar although $\ce{SO2}$, with a dipole moment of 1.62D, is more polar than $\ce{O3}$ (0.53D). As the diagram shows, the polarity of both molecules is due to the their trigonal planar shape with a formal positive charge on the central atom.