New York has an indexing system, in feet, for the geographic center of every tax parcel. 0,0 is somewhere in western Pennsylvania. Given a known position (eg: my own home) and a number of secondary positions it's possible to swing a measured circle around each of the positions and locate any property on a mapping program (I use DeLorem.)
We have a number of outlying counties where the realtors are not penalized (negligence on the part of the MLS) for failing to put proper addresses or locating instructions in their listings. On occasion pictures are reversed in the MLS, or missing or just wrong house.
Spent hours out in the hinterlands looking for poorly described properties (the listing signs were, of course, long gone.) "Route 8" is a poor address in Hamilton County .. dummies couldn't even put east or west side. How'd you like to drive 12 miles (each way), searching both sides, and still not find what you're looking for?
In any case, rather than break the knees of the listing idiots, went to GPS and plotting sales before leaving home. It's a pretty effective system. Will generally get me within a few hundred yards (multi-acre parcels will be centered fairly far off'n the road) and have an idea which side of the road to search on. Then, it just becomes a choice of one of 5-6 double-wide tin houses that fits the description. If I'm really fortunate, it'll be a real house (rare) among the tin houses ..
Especially useful if it's a nice day and I can use the airplane .. can't read street addresses from the air, but can cover much more ground, more quickly and enjoy myself. Don't get much joy from driving the car anymore ..
Spent under $300 on GPS three years ago, and am well ahead in dollars and aggravation ..