GPS Survey?

I know where 3 of the 4 corner posts are on my 40. If I use my handheld GPS and record the coordinates of the three known corners, is there a method for determining what the coordinates of the 4th corner should be?

The land is in Oconto County Wisconsin and they do not have a good GIS mapping program.

[SGPopp]

If it's a square 40, 1/4 mile at a 90 degree angle.

[gn83tm]

Easy enough to do in a CAD program. Send me the numbers if you want.

SGPopp - yes, but when looking at a 2" screen it is very difficult to say exactly where the corner should be.

gn83tm - Thanks for the offer. I will have to get the coordinates of the first three corners. I was going to do it this winter after the river freezes as I have to cross a river to get to one of the known corners, but I can drag up the canoe easily enough.

[Pokey Fisherman]

If the parcel sets perfectly square north - south wise is super easy because you can use the the lat of one corner and the long of the kiddy-corner point, and go to that lat - long. If it does not set square to the world, then it will take some calculations.

[gn83tm]

Originally Posted by TP180

gn83tm - Thanks for the offer. I will have to get the coordinates of the first three corners. I was going to do it this winter after the river freezes as I have to cross a river to get to one of the known corners, but I can drag up the canoe easily enough.

Let me know. It should only take a few minutes to do it.

[SGPopp]

Originally Posted by Pokey Fisherman

If the parcel sets perfectly square north - south wise is super easy because you can use the the lat of one corner and the long of the kiddy-corner point, and go to that lat - long. If it does not set square to the world, then it will take some calculations.

Yep, that's what I meant.

[REW]

http://forum.onlineconversion.com/ar...php?t-289.html

http://extension.oregonstate.edu/cat...pnw/pnw581.pdf

The other good thing to do, if you haven't done it already is to get the legal description of the land that you own.
Then, get a copy of the county map.
That way, you can look at the map to see where the legal description of your land states that your land is located.
Even with a GPS, it is a good idea to cross check the GPS readings to be sure that they agree with the legal description of the land.

If you refer to the 2nd article from the ones posted above, you will read the information about range, and section etc. Your legal land description should have legal verbiage that relates to the same information.
You can also obtain last years tax records that you paid on the land. The tax record and receipt will have a legal description of the land that you own.

It is really important to have the legal description of the land that you own. Just because you have three corners of the land defined, it is not necessary that the 4th corner of the land be on the corner of a square. It is possible that the 4th corner zips in or out - depending on terrain and legal description.

You can only use a calculation to determine the 4th corner, if you know the exact shape of the land. Maybe the land is square, rectangular, or an irregular polygon. The legal description will tell you that information.


I just went through this exercise with a recent land sale and because of a dispute in a boundary line, we needed special services to have a final rendering on the boundary line before the sale was completed.

REW

p.s.
Remember, it doesn't matter what the gps says, the only thing that matters is the legal description of the land, and that spot on the surface of the earth. If you get the agreement between the legal description of the land and the gps, great. But the actual boundary is determined by the surveyors previous surveys, which may or may not relate to real gps readings. The gps readins should match in the real world, but if you read the articles above you will find that there are fudge factors all over the world to get surveys to match actual earth conditions. You need to verify that your property is not part of one of these fudge factor survey condtions.

[ozarkeyes]

As suggested, get your legal description out, read thru it to familiarize yourself and I would suggest getting a USGS Quadrangle map too, they are handy and large enough scale to mark out your property. Since you know where 3 of the corners are I take it these have been pinned by a previous survey, and your 4th would have been too. Use your gps set it to feet start at one known pin and walk off 1320 feet, in the degree heading layed out in the legal description, set down a visible marker object, then go to the other known corner pin and walk off the 1320 feet again using the degree heading from that corner.When you get to your visible marker you should be close enough to use a metal detector to locate the 4th corner pin. This is hoping they used metal pins as corner markers!

[tv4fish]

Originally Posted by SGPopp

If it's a square 40, 1/4 mile at a 90 degree angle.

Don't want to "rain on anybody's parade here" -- but there is no such thing as a "perfectly square 40". Working off an aerial photo and a "mapping database" to get coordinates for your property corners is dangerous. IF you want to get "close" - OK, but if you're intending to put up a fence on your property line(s) or put up a deerstand based on your handheld GPS - you could be in for a battle with your neighbor(s).
TP180 - Is your legal description an "aliquot" part of a Section - something similar to "the SW 1/4 of the NE 1/4 of Section 5, Township __, Range __?" Also - When you say you know where 3 of the 4 posts are - are you refering to wood fence posts or actual surveyor's stakes??
If we want to get into details (and a long post by me) I can/will ? otherwise TP180 -- send me a private msg. and I can explain why you don't want to use your handheld GPS to do this.