General survey question on possibility of referencing using plat map

My wife and I just bought our first house and a bit of land. There’s a constant stream flowing through one corner, and the previous owner had built a dam and a pond. A few years ago, during a flood, the water overwhelmed the overflow pipe, eroded the dam, and blew out a 6-foot-thick section at the center.

Eventually, I’d like to topo the dam and surrounding area to determine how many cubic yards would need to be imported for repairs.
It would also be helpful to be able to find property lines/ corners (not for legal or building purposes, I would hire licensed surveyor) I have rover and data collector, local base with radio corrections and pay for CenterPoint RTX.

This type of survey or layout is different from anything I’ve done before, usually have a cad, vector PDF, controls set by surveyor, or can ask for easting and northings.

Trimble Business Center would be helpful for answering questions like: If I want a pond of a certain size, how much further would my dam embankment tie-in points need to extend? How many truckloads of material would I need to import, etc.? Right now, I have a lot of priorities after buying the house, so I wouldn’t pay for control points.

We own lots 6 and 7. I’m curious, using the given plat map, which includes extensive distance and bearing data, if I could recreate the property lines in Trimble Business Center (within 6 inches or so). And then horizontally refence the lines.

Is it possible to determine a grid coordinate point using Bearing-Bearing Intersection or Bearing-Distance Intersection alone? I understand that a bearing is a highly precise direction, but if I’m picturing it correctly, on a grid, without any coordinate to tie any one line or point to, you could have an infinite number of sets of two lines with identical bearing and distance, and their intersection points could result in an infinite number of coordinates.

I think I would need just one set of coordinates, it could be a start, end, corner, intersection, or a point-on-line (POL) with a known distance to or from that point?

Looking at this very blurry copy of the plat map (that probably was a hidden 1000$ fee in closing) do you see anything that could tie any lines to the grid?

Are there any online or public record resources that could provide the coordinates of any “found iron” markers called out on the plat? Or would best bet be to find a online listed control point in the local area and do a single point datum shift using RTX?

182 Graham Creek Rd Plat Map.pdf (116.3 KB)

If I was doing it, I would COGO the property line geometry over in Civil 3D without worrying about where it was in the world, fire up a new TBC project in your favorite State Plane coordinate system, go find the monuments and shoot them on the State Plane project, then bring in the property linework and best-fit it to the monuments as best you can. The monuments trump the mathematical coordinate geometry regardless where surveying property corners is concerned, but if you can find two monuments and line up the rest of the linework, it may help you find the other monuments or make assumptions about the other property lines.

1 Like

I would recommend a similar workflow.

If you are using Siteworks, once you have 2 points recorded, you can georeference the image to make it easier to find the rest of the data you are looking for.

I wish that was the case on the monument trumping the Math. I had my house surveyed and they found two in the front. Within the same month the house next door line was surveyed and guess what. The new surveyors decided to add new rebar for the corner lines. which my rebar was visible.
Use you GPS with your state plane zone coords thats after you find the corners. More likely you wont find all of them, so its going to be find some and either turn angles or let TBC help out. There are times you can draw lines in Google Earth and bring them into TBC to work off, if you have some reference object to go off. Then you would bring that in and export back to Google earth to see how much is needed to be shift to fit for layout. A little more work this way from the office.

Jonathan,

Since you have RTX, you can configure the coordinate system to align with the NAD83 system specific to your region. If you’re unsure of the correct system, you can use this site to identify it. Once determined, set up the coordinate system in Siteworks accordingly. The key step is to ensure the transformation is set from ITRF to NAD83, followed by selecting the appropriate zone. This process ensures accurate translation into true State Plane coordinates. Once configured, you can import the .cal file into Trimble Business Center (TBC) for seamless integration. Any points you shot in the field will now be State Plane. You can then rotate your PDF into the site by the points that you find in the field.

To find your zone you can use this site. https://www.stateplane.org/

1 Like

So I have Siteworks and TRIMBLE BUSINESS CENTER but no access to Civil 3D, is Civil 3D 100% required?

I have used the COGO menu in siteworks on my Trimble T7 Tablet plenty… But I’m guessing that you are talking about something competently different

Civil 3D is not a requirement, but it is the best way I know to re-create the geometry of a plat or legal description. TBC works, but I have found it to be painful in comparison. Here is a quick help on lines by bearing in TBC, and hopefully someone else in the community can weigh in with more TBC COGO tips. Inputting property lines by bearing | Trimble Business Center

Interesting point as to what “COGO” actually means. To me it is shorthand for “coordinate geometry”, and its broad definition covers a number of things related to points and lines associated with real-world and/or relative geospatial coordinates. It is technically incorrect to use it as a verb, but that was common survey lingo where I learned it in reference to re-creating the coordinate geometry of a plat or legal description. I suspect some mid-western language stereotypes are at play here :grinning:

You can in TBC use the COGO create COGO function to key in a plat. Or you can do it by bearing and distance with line string. I compile plats every day in TBC. Now you will need to go to project settings and go to set your azimuth to bearings as most all plats are usually in bearings. If you use the create cogo you can have it automatically create points at the angle breaks and PC and PT in curves. A quick way is to do this on a known datum. Like state plane. Reach out to google earth or your local GIS and eye ball a couple points that are close to where your property is. After you do the compile hold one rotate to the other. It is very possible the plat is not on a known datum this will get you close. Once you have found all your corners take that same compile and inverse to find at least two corners across your property that fit well. Distance wise. Draw a temp poly line from those two on the plat and the same two you observed. I usually make a selection set out of my compile. Move the compile along that temp line middle of segment to the middle of the two points line and then rotate. Then go check the rest to see how the fit. You might need to do this several times to find the best possible fit. Really need a Licensed Surveyor. But if the mons and math fit it’s probably close enough for what you are wanting. Next thing to remember depends on where you are the Grid vs ground issue. Here it’s only about a tenth of a foot per 1000 uft. It could be way more where you are. Most plats are ground distance unless otherwise noted the bases of bearings might be NAD83 state plane xxxx but not necessarily so. If you are out of the USA then you might be dealing with grid ground or ellipsoid distance everyone does some things slightly different.