help about SWR!

all
I'm so confuse of SWR!
In the book, It defined SWR as |Vmax|/|Vmin|.
What's meaning with the |Vmax| and |Vmin|?

If transmission line is matched, line impedance=generator impedance=load impedance, the voltage along the transmission line is constant. In case of mismatch when load impedance is not equal transmission line impedance the reflexion occurs. It causes voltage minimums and maximums to appear along the line, so the voltage along the line continuously changes with distance from load. At some places we have max. line voltage and after quarter of wavelength we have min. line voltage. Ratio Vmax/Vmin gives measure of mismatch, VSWR (voltage standing wave ratio). It is 1:1 when line is matched and 1:∞ at short circuit or open.

I think i have attained it.

Thanks a lot!