Apps for surveying prospective land

Not sure where to post a thread on land, but hopefully this will merit being moved if this is misplaced.

https://permies.com/t/56215/start] This thread was helpful for someone who is about to move to land, but what about for people who are actively surveying land?

My main question right now is what works well in the field: what can I use to walk a piece of property and determine its boundaries? If I know a plot is 10ac at 330x1320 sq ft, how can I determine on foot where the property begins and ends? I am going to walk a property I've previously visited and use Fields Area Measure and GPS to see if my location and distance covered match the plot map, then use signal tape to mark the boundaries for my own future reference. I'm also going to try Planimeter since I think a second opinion is always best. Of course this won't always work if one can't get signal on site, but I'm about to find out how granular GPS can get with possibly limited signal.

For determining solar access to site, there's an app telling you where the sun will fall at any time of year based on where you're standing, using GPS. I haven't used it because it's not on Android, but a friend recommended it for solar installations and gardens alike: Solmetric ISV. I'm going to test Solar Shading and share my results.

I guess everything depends on how accurate you want to get. I am pulling a lot of this information from class word I did in 2003 so it is a bit fuzzy but I think most of the details are still accurate.

The issue is that GPS can be VERY unreliable under tree cover. You can easily get in accurate locations of 20+ feet. This is even with VERY good (read expensive) GPS equipment.

Low cost GPS equipment (read your phone or consumer grade GPS) can and likely is still off by 10 feet in open conditions. This is due to clouds, humidity and other environmental factors.

So while you can get a decent feel for where your property lines are with a GPS device, please don't solely rely on it as the final truth. If you really want to know where your property lines are you will need to hire a surveyor.

That all said, if you don't need exact property lines, I would check if your county has a GIS department. If they do there is a high likelihood that there is a online site that will allow you to look at property maps. Often you also can see an areal photograph of the property at the same time. From this material you can generally get a decent idea of where the property lines are. If there is nothing online check with the County and talk to the GIS department and see if they can give you a printout or screen shot of your property with property lines. My feeling is that this will give you a more accurate reflection on your property lines then trying to do it with a GPS device.

Hi Bernard, I should probably not have written "surveying". Though that is what I am doing in a very inexpert way, it implies that I think my findings are accurate or legally defensible/actionable. I know they're not.

In my experience with rural land, realtors are somewhat indifferent (understandably) unless they are reasonably certain of a potential sale, and they don't know the properties they're listing beyond documentation. Owners are often absentee and I LOL when I read advice in books that one "walk the land with the owner". So what I am doing is trying to ballpark on the ground for planning purposes, ideally with an aerial and plot map.

Planimeter claims to have GPS accuracy within 9 ft. You can specify how precise you want the location service to be, but you have to wait while it locks on.  Within 24 feet was about as much as I had patience for as it was fixing to rain.

As far as measuring slope, I tried Bubble Level (which gives degrees off 0 measurements on two axes, not just a visual level and airbubble), and found it to be accurate within the USDA-NCSS soil survey's ranges of slope for a given soil type. Very little exceeded what I expected and that only in limited areas, by 5-8 degrees.

I do have an aerial photo, as well as the plot map. I had superimposed the plot map over the aerial to guess how far I should walk. But I hadn't thought to check the GIS by county. Though they probably don't have any additional info on this property, they would be helpful to check many others. Thanks!