If I see an Apple shop across from a parking lot, it may not be immediately obvious that the land part of the valuations should be similar. I could see the crowd systematically getting this wrong.
Having said that, it's not a damning criticism. I think LVT is a good idea, and people are generally going to know what piece of land is worth more than another. You can then stitch the relative values to some sort of exchange-based anchoring to give your map real dollar values.
I do tend to think a Harberger system makes a lot of sense, though. Maybe something a little bit like:
- Everyone puts a value on their land. We take the total, figure out what percentage needs to be taken, and everyone pays their share of the tax take accordingly.
- Your land is for sale at the price you put, but you can change up the price if you don't want to sell it, and thus pay up extra tax. If you have land set at 1M and someone comes and offers 1M, but you don't want to sell, you can pay the tax at whatever price is too high for him, eg 2M would double your tax. The offer needs to be firm so that you have an actual choice, someone can't just double your tax bill on a whim.