Plot Ratio 7

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

What does plot ratio means?

In simplified terms for explanation, a plot ratio is how much space you can build up on a particular piece of land, for example, for a piece of 10,000sqft land, if it has a plot ratio of 1:2, that means a building of 20,000sqft can be built on it.
This ratio is determined by the state authority.
But, on top of plot ratio, there are other considerations like set back area, height restrictions.......
There is not fixed definition on high and low density development, it is a relative comparisons between the number of units to the land size of a development

its counted as nett floor area or gross floor area?

Thanks @vince2602

gross floor area, the common area, service area, traffic circulation...included

Is there any plot ratio for a residential bungalow land? Can the owner tear down his old 1 story bungalow and built a 3 storey bungalow? What kind of approval he needs to get and from who?