While marking some lines today, a client was telling me about his GPS being about 15 feet off on a corner. I didn??t think much of it until later near another corner, he was hovering around it with his phone and commented on how close he was. I got a closer look and was pretty amazed at what I saw. Downloaded the app and it is pretty cool. Free trial for about 10 days and then I??ll decide if I want to go further.
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I love it.?ÿ I've had it for over a year.?ÿ It pays for itself.?ÿ ?ÿ?ÿ
It's a great app. I subscribed and use it daily. It easily pays for itself. ($99 a year)
It's great for looking where a section or 40 corner should be and will get you close enough to start looking for evidence.
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I've been using OnX Hunt for the same purpose.
It shows the boundaries very close and gives the name of the land owner and costs $20 a year for Texas.
Today I was contacted through the amateur benchmark hunter forum, probably because at some point I mentioned State Plane Coordinates in a post there.?ÿ The guy wanted help turning SPC into lat-lon.?ÿ
He bought about 280 acres (not aliquot) of wild mountainous land (>10k ft elev and 1000 relief) in a somewhat remote area in the Southwest and the surveyor's plat has "modified SPC" coordinates and a (combined?) scale factor.?ÿ He thinks there are stakes for his corners and needs search coordinates for his phone's GPS.?ÿ I cranked out lat-lon from Corpscon, mentioned the NAD83-WGS84 offset, and warned him not to use the numbers to set stakes - they are just search coordinates.
He told me he has a "known" corner, and I was rather worried because my grid numbers miss that by over 1/4 mile (or 200 yards using modified SPC).?ÿ I then learned it is just from OnX, and not a found stake.?ÿ It's probably too soon for OnX to have his new parcel entered, so I'm confused about what it is.
In that environment, when they get the plat entered into their data, how close would you expect OnX to be??ÿ Will they convert modified SPC to grid before going to lat-lon?
The formula for OnX is:
Error of underlying data + error of input + error of missed translations + error of phone gps ?ú square root of the IQ of the user ?? 3
Roughly..