method to valuate townhouse land valuation

G’day fellows,

I am new to the whole world of investment, and i am still learning. :)

Can i ask if I would like to buy a townhouse, is considering the land valuation worth doing it? if so, what’s the right way to calculate the approximation of the land value?

For example, on qld land valuation site (https://www.dnrm.qld.gov.au/qld/environment/land/title/valuation/search) , the land is 1.5ha and valuate at $4,100,000 and the townhouse has 392m2 of land and the building is 20yo. I wonder what method you guys evaluate to spot if the asking price is a good deal or bad deal?

Thanks in advance.