I’m hoping for some guidance from the surveyors out there. I’ve been asked if I can help someone find their corners. They have a plat, so I can do a drawing in CAD and transfer it to my Reach unit, the problem I have is that there are no points called out in state plane coordinates. Would the original surveyor have the corners in state plane instead of just the lines and angles? If I can find one corner it seems that somehow I should be able to use that to find the rest. How do you pros do this?
If you’re not a PLS you shouldn’t be doing this, so be very careful if you go digging. Honestly the best way is to use a magnetic locator like a Schonstedt, go to what appear to be obvious corners and pace it off. You can put it in CAD but you’re not going to find them any faster. You can create points in Google Earth using the fence lines and the general shape and distances from the plat and import those in. If you find two you can localize and get closer to the others, but you’re not going to get consistently close until you localize to 3 or just get lucky.
I’m not a surveyor but I can try to answer. Do you mean a building? Do you want to mark out a building on a plot of land? Is this about something else?
All plots have their coordinates designated in state plane coordinate system SPCS (2D map coordinate system as in other countries as well). There are no plots without coordinates.
You can visit your county’s GIS web page and hover the cursor over the property corners, it will show the corners coordinates. Accuracy of most GIS systems are pretty vague but will get you in the ball park. Find two corners of the property that you are “surveying” and write the coordinates down. In your CAD system, draw the boundary out per the maps bearings and distances, hopefully the survey map will close mathematically but probably not.
Input the coordinates you saved earlier and then translate/rotate the property drawn per the survey map to the new coordinates. You’ll need to know what coordinate system your state uses to setup in Emlid software.
Once you have figured out the coordinate system, you’re good to go.
A tidbit of advice… You can get into a lot of legal problems if a neighbor starts questioning what you’re doing. CALL THE LICENSED SURVEYOR WHO DREW THE ORIGINAL SURVEY MAP. His fee would probably be far cheaper than the legal fees you might have to spend defending and explaining what you are doing.
The question seems to be about the lack of plot coordinates. Plot coordinates can be obtained from WFS services with centimeter accuracy for free or from geodetic centers for a small fee. Do not use WMS services, because they only determine plot contours based on aerial photos and have decimeter or meter accuracy.
Surveyors very often make mistakes and sometimes even make a living from their own mistakes. Sometimes it is worth checking what is going on and modern equipment makes it possible.
This is not true. Many plats are built from using a TS on an arbitrary coordinate basis by resecting found points and locating the rest. At least in the USA RPLS’s do not publish coordinates on plats. Some people use GNSS now when applicable so the CAD data may be on actual State Plane but they still don’t publish coordinates.
The neighbor can sue for anything they want regardless of your actions. Not to mention that they are their property corners as well so digging a hole to find a monument and potentially disturbing the monument is a no-no.
The RTK measurement itself looks like this, but I think you know this:
If you perform an RTK measurement in relation to a public CORS base station, the measurement result will be in the NAD83(2011) coordinate system, i.e. the 3D system. The result is in NAD83(2011), because the base station coordinates are in NAD83(2011).
Then this result must be transformed (projected) to the 2D map system (SPCS), in your case NAD83/Georgia West (ftUS) EPSG:2240.
The transformation from NAD83(2011) to NAD83/Georgia West (ftUS) can be done in several ways:
If your receiver’s software has the ability to automatically transform, you will have the position measured in NAD83/Georgia West (ftUS) right away,
You can use Proj application installed with QGIS application or downloaded from Internet and run cs2cs command,
You can use QGIS application and import the results of measurements in NAD83(2011) as a layer and then export this layer in NAD83/Georgia West (ftUS).
@michaelL@jan.wodnik
Thanks to all for the feedback. I do have the county property shapefile and I can use their information for a start. Unfortunately, the County info does not line up with the measurements on the plat, so it’s of little value.The original surveyor is 6 months behind, so that’s not an option for this project. I have suggested my friend see if he can borrow a metal detector and he is pursuing that.
For what they are doing, to be WGS84 relative immediately and to be guided quickly to the area of where the point should be this is actually very easy, and anyone can do it regardless of their software infrastructure. Do you know what the OP’s capabilities are? Sounds pretty new to me. You lost me as soon as you expected coordinates on a plat.
I will not comment on this any more, but I would like to warn other users who would like to perform a transformation from WGS84 to NAD83(2011), to first check the accuracy of the transformation, because it is of the order of meters.
We’re not even talking about projections. They want to turn their receiver on, open flow and stake to property corners. Since there are not coordinates on a plat, NAD83(2011) is irrelevant.
