What is plot ratio and how to determine that the development is high or low density through plot ratio?

Ya, great input by Vince. Correct me if I'm wrong. Plot ratio for the high rise dev is higher compared to the landed ones. Which means the landed that we own is lower compared to the specific high rise as its build upwards and all...

@JohnL 

Do you know what is the formula to calculate plot ratio? 

What ratio is considered low or high? Thanks

Plot ratio in every area is varies and all depending on the local authority planning,  zoning, category of land as well as purpose of use. 

@jordanchen1981 good sharing