Home Forums Hunting & Shooting Backpack Hunting Thoughts on onX maps

I have been told the mapping and property info data is based on the county assessor's tax data. I wonder if that means either OnX goofed something up in compiling that data, or if your county believed you own that other property???

If thats the case a guy could be paying taxes on what isn't theirs.

I believe that Onx uses the same data for the app and the chip. I find that the Garmin is more accurate than my phone so apparently the difference is in your hardware, not with Onx.

The land ownership data comes from the state/county Cadastral and is only as accurate as the cadastral. I have seen where a surveyed corner was 50' off from the GPS coordinates. Probably would not result in a trespassing citation as game wardens and such use the same data base, but can make a significant difference in a legal access claim and/or whether a parcel of land can be insured with title insurance in a land transaction without additional proof of survey.

Very true. I bought some land in central Montana a few years ago and relied on the Cadastral rather than a survey. The Cadastral showed the land being on both sides of a trail, with about 200 ft of the land on the west side of the trail and the rest of the land to the east. So based on that, I bought then had a log cabin builder take a look at the land and find a good place to put the cabin as it was being built. It turned out they thought the 200 ft on the west side of the trail was the best location.

When they hauled the cabin out to the land and started to prep the spot for placing the cabin, the guy who owns the adjoining land asked them if someone just bought the land, as he had been misled by the Cadastral when he bought his land and had an actual survey done. That survey showed that the land boundaries were off and my land did not include the 200 ft west of the trail.

That was a close call, as I wouldn't have wanted to have had to move the cabin and clean up the mess I made on the other owner's land.

Fence lines out west more often than not are 30-60 yards off of where OnX and/or GPS says they should be, let alone 50 feet. I am guessing GPS would show the "correct" location vs what was determined by a Gunter's chain 150 years ago, but I am sure that could be contested in court if a citation was issued.

Variations could also be from your GPS being set to WGS84 and the mapping data being based on NAD83, or vice versa....Lots of possibilities when it comes to that kind of thing.

I don't just rely on GPS data, I have BLM maps for most of the areas I plan to hunt(three ring binders for each state) and I carry a computer in the truck to access county assessors data. It is surprising how many times there is a difference.

The maps are very old school BUT it is nice to be able to set up a calling route(coyote hunting) through new country in the camper at nigh and use the GPS to navigate during the day,

Fence lines and surveyed monument corners are two very different things.

Too many relying on GPS to flirt with boundaries do not understand your last sentence. IME also why some report "accuracy" issues when comparing devices.

95% of us are hunters who just like to know about where we are and to stay legal. We know nothing about that surveying and alphabet stuff.

True. I typed faster than I was thinking.
I was referring to old USGS surveys in general, whether fence lines, monument corners, geodetic marks, survey markers, etc.

The Colorado/Utah/Wyoming tri-state boundary monument corner is easily 50 yards off of where my GPS says it should be and IIRC the OnX property overlay was off 20-30 yards in the other direction. I do not recall what settings my GPS was on when I realized this though, which may have made difference...

I prefer to just get 2-3 miles into USFS land if possible for the species/tag I have, and only use the GPS to see how far I hiked out of curiosity. It makes things so much simpler.

Agreed. I haven't noticed the WGS84 and NAD83 to be 50 yards off....more like 10-15 yards in most cases but with the perfect storm of software incompatibility, thrown in with poor signal strength from cloud cover/canyons or cheaper devices, a guy could be pretty far off their mark. Best to be used as a general reference only.

It is nice to know that if a watershed divide is a unit boundary, even if the GPS is off by 100+ yards you know that the main, huge ridge right in front of you is the true unit boundary. Checkerboarded areas with lots of seemingly random allotment fences can be a nightmare but if the property overlay shows the "next" fence 50-100 yards over there is the property boundary, it is pretty nice to have too. I think these types of instances are where this technology is most useful.

This is definitely the easiest.

Can’t speak to other states, but in NM, some of the easier units to draw have patches of public scattered with private, throw in unit wide elk authorizations and it can get interesting.

Have found a phone call or knock on the door goes a long ways when we are flirting real close to deeded.

It sucks that the easier to draw tags generally have less public access and a more confusing mosaic of private land puzzles, but it is what it is, and if a guy gets confident in navigating the ownership jungle he can probably get some decent tags quite often.
That's just my optimistic way of saying do what you have to do, to get the opportunity to kill things.

Or to GFY. Leave my Gila elk tag alone.

Your Gila tags are safe from me.

100 tags, 101 applicants. I’m the one.

It's off my 100 yards or more on portions of my property. I think the OnX property lines are fairly accurate assuming the source they pull from is accurate. The property lines on my land that are off are somewhat different in the deeds compared to the tax parcel maps. The deed references natural features. The tax map just draws approximate lines. It appears that OnX uses the tax maps. However, this is a former farm of about 500 acres that was divided 4 ways about 25 years ago. I'm not sure it was ever surveyed.

I love ONX & use it a lot. Fantastic for scouting and for in the field.

I use the ap on my IPhone & the issues ive had with it updating my position too slowly would take place w/ other aps & GPSs so I don’t lay that at ONX’s feet.

I'd hazard a guess that some of the slow updates are due to one's location and time of day. When/where can have a significant impact on the number of satellites available and the orientation of those satellites for location. Doing surveys some years ago, we had more satellites in a better orientation from 11a-2p than any other time of the day.