Extrapolatin grid coordinates...

mofugly13

Full Member
Jan 30, 2015
198
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San Francisco, Ca
Primary Interest:
Prospecting
Is there a way to extrapolate grid coordinates from a MTP? Or any other map? My claims lie bordered by patented lands, and on online topo maps that show land status, I can put the cursor on corners of my claims and get grid coordinates from that, however these are not very accurate. Short of hiring a surveyor, how would someone determine the grid coordinates of their claim corners.
 

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Is there a way to extrapolate grid coordinates from a MTP? Or any other map? My claims lie bordered by patented lands, and on online topo maps that show land status, I can put the cursor on corners of my claims and get grid coordinates from that, however these are not very accurate. Short of hiring a surveyor, how would someone determine the grid coordinates of their claim corners.

Not sure what grid you are using? Neither legal land descriptions nor mining claims use a grid system.

The MTP is not an accurate ground map. It is only meant to indicate land status of individual portions of the Public Land Survey System. For the actual physical locations of those individual portions of the Public Land Survey System you will need to find the Survey pin and go from there.

Since you claim is bounded by a patent there is another approach that works. Download a copy of the patent survey. It will accurately portray compass directions and distances as well as the survey pin locations.

Heavy Pans
 

I understand what you're saying about the MTP. So, I would actually need to find a benchmark on the ground?

And, does benchmark = survey pin?


I'm accustomed to seeing a bronze or brass button cemented into a rock with information engraved on it. Is that what I'm looking for? Are those called out on an MTP?

The grid I am referring to are Lat/Long coordinates. As in, my claim is the S1/2 of the SE1/4 of the SE1/4 of section XX TWP XX RXX MDM....

Once I am physically on the ground, what is the process for putting myself on the corners of this hypothetical claim?


What would be my starting point? Would there be any way to determine the coordinates of the four corners of my claim before I set foot on it?

Currently, the corners of my claim are marked as I described in my first post. Using an online topo map, I places the mouse cursor at each corner, and recorded the coordinates it gave. Then I plugged those into my phone GPS and travelled to each of those locations. I'm sure that the compounding of errors using this method would cause me to be way off the actual corners.
 

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Here is a document about GPS accuracy. https://www.gps.gov/systems/gps/performance/accuracy/. You will never find your corners accurately with a GPS but you can to about 16 or so foot accuracy. I would just stay within those bounds to be on the safe side. I imagine if you zoom in on My Land Matters maps and use those corner coordinates you will be very close.
 

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Is there any liability from you perhaps mining outside your mining claim?
An example...logging. Timber cruiser marks an approximate line (being slightly more familiar with surveying).
The liability of harvesting someone else's timber is significant. Usually the liability is high enough that they do one of three things...
A: hold off the line by some comfortable distance.
B: come to agreement with adjacent land owner.
C: hire land surveyor to mark line.

If you want it marked correctly, hire a surveyor.
 

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Just back off 15-30 feet from the boundaries to account for errors in gps and you are good.
 

Getting within 15-30 feet of the true position of an aliquot corner using handheld GPS would be difficult at best.
First off you need to measure the actual section corners.
Sections are not all nice one mile squares and quarter corners are not always found halfway between section corners and inline. Some of the PLSS lines that are shown on the maps are based on field data...some of it isn't.

BLM has a PLSS data layer that includes metadata for each corner which explains the expected accuracy of the position.
That's where I'd probably start.
Visit the National Map to download the PLSS layer and work with it in QGIS (free GIS program).
 

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I'm in the same boat with the area I may be claiming. I have the PLSS grid on the topo, but the grid line is as wide as the creek on the map. (about 50' wide) So I can only guesstimate where the actual claim marker should be from sat photos. I'll need to bring a surveyor in to accurately set the post. Luckily, the cost can be used against my annual work requirement. The first post I set will be the benchmark for the rest of the claims. There's a lot of dashed contour lines in this valley, which means nothing has been accurately surveyed.

So, we'll set the posts in good faith, and then bring the surveyor in to correct them.
 

Back in the day, before GPS..we could get pretty close with a compass and hip chain. Still have to have some understanding of basis of bearings and declination. Then some basic math skills to correct up once you get to a known corner.
 

What I have done to get me close is to print a usgs topo of the land section Im working on. Then with a ruler and sharp pencil divide the section into quarters and quarter quarters or smaller. Now with those corner points overlaid on the topo I used an app like US topo maps and marked those points in the field compering my topo gps position to my paper map.
I recently marked another property that had a patent cutting into one corner and was able to find the patent lines and pin with help from gps also. In this case the Onxhunt app really helped as it shows the property lines and they were dead on for the pin, so sometimes you get lucky and things line up.
Unfortunately without some real surveying skills its not always accurate and we try to hack things in sometimes.
 

Is there a way to extrapolate grid coordinates from a MTP? Or any other map? My claims lie bordered by patented lands, and on online topo maps that show land status, I can put the cursor on corners of my claims and get grid coordinates from that, however these are not very accurate. Short of hiring a surveyor, how would someone determine the grid coordinates of their claim corners.

Pull the county plot map for the patented property. It's a public record and you can be sure what is theirs and might be yours. They're usually about $50 but sometimes if you just want one just this once they will give it to you for free.

Not all land owners know where their legal boundaries are and just "know" what is theirs. Had a family once said they owned all of my claim and said they were going to call the sheriff - they are friends after all and he will "make it hard on me'. About an hour later SO shows up wanting to know why I am mining on "their" property. I show him the county's own record, where the survey markers are that I could still find and why certain landmarks are the way they are. He walks over over and breaks the bad news to the sheriffs friend. I wished I would have recorded the reaction when he found out his property is only half of what grandad told him it was.
 

Pull the county plot map for the patented property. It's a public record and you can be sure what is theirs and might be yours. They're usually about $50 but sometimes if you just want one just this once they will give it to you for free.

Not all land owners know where their legal boundaries are and just "know" what is theirs. Had a family once said they owned all of my claim and said they were going to call the sheriff - they are friends after all and he will "make it hard on me'. About an hour later SO shows up wanting to know why I am mining on "their" property. I show him the county's own record, where the survey markers are that I could still find and why certain landmarks are the way they are. He walks over over and breaks the bad news to the sheriffs friend. I wished I would have recorded the reaction when he found out his property is only half of what grandad told him it was.

Not being argumentative, but speaking from experience..that's just not how it works.
That does generate a lot of new survey work.
Most "county maps" people pick up are tax assessor maps which don't mean squat as to where people's ownership is located on the ground.

Then there are recorded survey or parcel maps, which are just a snap shot in time.
People buy additional parcels..there are boundary line agreements/adjustments and adjudicated court decisions. It's actually much more complicated than looking at the county land ownership mapping with the nice aerial in the background.
 

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I am not so concerned about my claims boundaries as I am on good terms with the owner of the patented property. I am mostly curious to how the corners would ultimately be established.

If I were to hire a surveyor to come mark my corners, what would be his very first step? What would his process be in locating that first corner point? Is it easy money after that first point is established?
 

First step would be research.
Many people say they only need one corner marked or just one line, thinking they will get a better price, or somehow that makes it more simple.

Truth is many times the surveyor has to survey ALL of your lines, the lines of your neighbors, and section corners located up to six miles away in an extreme case.

Best bet would be to speak to a land surveyor. They usually will do enough free research to get a handle on what your survey will involve. Unpatented mining claim surveys are not very common, but I bet you can find a surveyor to do it for you. Surveying patented mining claims can be expensive. It is probably more than your situation warrants.

I like the idea of coming to an agreement with the owner of the neighboring land.

By the way....the term "benchmark" in surveying jargon is primarily associated with a point of reference for purposes of establishing elevations.
 

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If you can find a surveyed corner monument on the patented land or an established PLSS benchmark, that can be your starting point because it is a "found" location.
Then, using a real GPS (not a cellphone app) you can project a waypoint in any direction for any distance. I have a Garmin Montana 660 and it will deliver accuracy to about 3 meters in open country consistently. Set it to WAAS and you will have the best PDOP. Turn on waypoint averaging and collect several waypoints and you will see accuracy to about 1 meter.
Being within pissing distance of the actual corner is probably good enough by anyone's measure
 

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