What are Florida property assessed values based on?

Are you referring to just the land or to land that has something built on it? The land? No clue, I don't deal in just property there. Land in and of itself depends completely on where it is (lakefront, a busy street, lots of trees, agriculturally viable, business area, zoning, airport nearby, etc). Homes in FL I do do. With most homes it is based on market value, yes. There are lots of specifics to it and several people look at it before an amount is set. Experience, levels of professionals checking each others work, and guidelines.

The best answer I can give you no matter which of the two you're looking for (land or home) is go to a realty site and look for features similar to whatever it is you're selling/trying to buy that has SOLD in the last 3-6 months. That will give you a decent idea. Always remember, no matter what industry you're talking about, something is worth what someone will pay for it.