1.North Indian Chart---here , Horoscope is calculated Anti-clockwise from Ascendant, a circle divided into 12 divisions/houses (30 degree each)(ascendant is drawn on top)....here calculation is from ascendant..Practised in North India in places like, Delhi,Lucknow,etc.
2. East Indian Chart----here, Horoscope is calculated Anti-clockwise from ascendant , here also the same 12 houses/divisions (but generally the outside circle is not drawn), Mesh raashi always stays at top in the kundli drawn..but here also calculation is from ascendant..Practised in East India in places like Kolkata, etc.
3..South Indian Chart---here, calculation is done Clockwise from Ascendant.. it looks like a rectangle (actually not).. it has the same 12 divisions..here calculation is from ascendant, but clockwise..Practised in South India in places like Chennai, Thiruvananthapuram(Kerala), etc.