The appraiser on my 40 acres asked me for a list of everyone I'd ever talked to about buying it

Needed a value on a piece of raw ground for an estate matter. I figured it'd be quick, it's a rectangle with a gravel access and a creek across one corner.

The appraiser showed up in a truck with a state map book, the paper kind, and told me straight off that there hadn't been a comparable sale in this township in about two years. He asked whether I'd ever had an offer on it, whether anybody had ever approached me about the timber, and whether the neighbor to the south had ever asked about the strip along the fence line. I said yes to two of those and he wrote them down. He said unsolicited offers aren't sales and don't go in the grid, but they tell him whether he's in the right neighborhood before he goes looking.

Then he drove. Three counties over five days, pulling sales of anything with a creek, anything with road frontage under a quarter mile, anything with tillable acreage in that range. He came back with four sales, all of them 20 or more miles out, and a page explaining why each one needed adjusting for distance and market.

The report took eleven days. Cost me a good deal more than a house appraisal and I understood why by the end. There's no database that would have done any part of that. He got out of the truck at the creek crossing and walked the bank both ways because he wanted to see how much of the frontage floods.