[caf]

Land taxes are certainly in use around the world. My "rates" which fund the local government are based on the "unimproved land value". If you are unhappy with the land value determination (presumably because you feel it is too high) you can object and present evidence - for residential property that isn't too hard because area sales records are available and the replacement cost of the improvements on the land are reasonably easy to estimate and subtract from the sale price. No doubt unique businesses like airports get professional appraisals that painstakingly put an estimate together.