bloke - learning about longitude/latitude/google & a video

[iiipopes]

Let's see: 360 degrees in a circle, 60 minutes in a degree, 60 seconds in a minute, so that equals 1,296,000. The earth's circumference is @ 24,900 miles at the equator, or about 131,472,000 feet (give or take a couple of miles). So 131,472,000 / 1,296,000 is, indeed, about 101 feet per second of longitude arc at the equator. At the poles, where all longitude lines converge, the distance between longitude lines is zero, and the cosine function in degrees will tell you how long the distance is for one second of longitudinal arc at latitude. for example, south of Memphis is about the 35° line of latitude. cos 35° is @ .8191, so multiplying that together and you get a due east-west distance for a second of longitudinal arc on the south side of Memphis as @ 83 feet. And then for other actual distances, well, I don't want to fill up the bandwidth with trig functions.

[iiipopes]

bravo !

Thanks.

[alfredr]

Bloke, I don't know what it would cost to hire surveyors to do that for you; it is equivalent to renting very good equipment and very good GPS service (which is not cheap) and getting someone who knows how to use it. A couple hundred dollars would be my guess.

I believe you asked for suggestions on how to do this before, and I believe I suggested a low tech way.

If you can see from one end (corner) to the other and can get a helper, it would be pretty easy. I assume you cannot see all the way in one shot due to terrain changes and vegetation in the way. You need a couple of tall sticks (10 or 12 feet), a bunch of stakes (3 or 4 feet) and flagging tape. Plant the tall sticks at the corners with flagging tape on them to make them more visible. Then start off from one end in the direction of the other end (compass heading if you can't see the other tall stick), and every so often, plant one of the stakes, also with flagging tape on it. You may have to work from both ends. You want to have three or four of your stakes visible at all times so that when you have a (crooked) line from one end to the other, you can sight along several stakes and line them up better to place the stakes, (This is what you expect to have to do even if you use GPS, aka "justify") until they are straight. A helper to sight while you move stakes (or vice-versa) will speed it up, but you can do it alone.

Yes, the GPS coordinates on the compass app on the phone is not precise enough for survey work and as you have seen, they don't use the same units as surveys do, minutes/seconds vs. digital fractions. It only seems to be within 10 feet on elevation also. I don't have any experience with a GPS device such as Garmin.

[hup_d_dup]

I've gone through all this on my own property. The property survey gave the coordinates for a corner marker in the woods several hundred feet from the street. I used a phone and google maps. The results were ambiguous and unstable. I knew I would have to clear some cover but I didn't trust the location(s) given by the phone.

Using a compass, the survey map, sight lines, and a 150 foot tape measure I went to the approximate area that the marker should be. After clearing out about 1000 square feet of ground cover the marker was found.

After the SW corner, the NW corner was much easier to locate. No need to bother at all with the phone.

One interesting thing I've discovered by doing this is that there is a rubble fence along the southern property line. You might not notice it as it is overgrown and is sinking back into the land, but it is clearly there. I have begun to slowly build it back up. It dates from the time this was farmland in the 18th & 19th centuries, and the farmers would clear this rocky soil by moving rubble to the property line.

Hup

[iiipopes]

Almost 60 years ago, my maternal grandfather purchased some land adjacent to his farm to increase the size of his farm. He wanted to pour a concrete corner post to anchor barbed wire fencing along the property line, which was the section line for that plot. According to survey, he was supposedly right on top of the section corner marker. Not taking anything for granted, He dug down until he hit a large rock. After clearing the dirt, the "X" was very visible on the top of the rock. Yes, he was indeed at the corner of the section. As a person is supposed to do, he proceeded to cover the rock back up, undisturbed, and poured his corner post, knowing he was exactly where the survey said he should be.

[alfredr]

Incidentally, when a survey says,"I. P. F.," iron pin found, around here is quite often what appears to be an old truck axle or some other shaft from some old equipment. I. P. P., iron pin placed, will be a piece of rebar.

But why bother with LED lights? In daylight, you may not be able to distinguish it at some distance any better than flagging tape on top the pole. Flagging tape will be cheaper and easier to attach.

[alfredr]

I don't know what you have in mind for LED lights. Would the terrain allow for seeing a light on top a pole anyway? That is why you place stakes and line them all up afterwards, three, four, half a dozen at a time as you can see them. I have done this myself over about 300-400 feet.