Working on a project deeding some lengthy easements (some 10+miles) to the State of NH. State standards specify accuracy requirements for directly occupied corners and those used for control supporting the survey.
Centerline description was done by others using a rectified orthophoto
Easement ends were tied to property corners and follow accuracy requirements.
No monuments were set along the way.
I don't see the math on the centerline being subject to state standards but would be acceptable, .5ft, 5ft 15ft or is it even relevant? Thoughts?
I would make sure the intent of the location is clearly described, using qualifiers to further detail the description. for instance, if the intent is to be adjacent to and parallel to an existing r/w line or section line - say so in detail.
>Easement ends were tied to property corners and follow accuracy requirements. No monuments were set along the way.
Sigh.
Making it easy for schmucks like me to come along later and say with certainty where the easement limits are on the ground. I have a 50' wide telecommunications easement that was based on a pole line built by the Army in the 1920's and never surveyed, just crudely mapped. Now the poles are gone and the powers that be want me to tell them where it is due to a pissing match with the Dept. of Transportation, to the foot. Can't do it. No way, no how. Not with my stamp on it.
> Working on a project deeding some lengthy easements (some 10+miles) to the State of NH. State standards specify accuracy requirements for directly occupied corners and those used for control supporting the survey.
>
> Centerline description was done by others using a rectified orthophoto
>
> Easement ends were tied to property corners and follow accuracy requirements.
> No monuments were set along the way.
>
> I don't see the math on the centerline being subject to state standards but would be acceptable, .5ft, 5ft 15ft or is it even relevant? Thoughts?
Good project to create an ulcer on.
IF you can run it on the ground from the controlling monuments without big math adjustments I think you are OK. But I would want to check graphically how your solution fits that ortho photo.
IF it were me, I'd sequence it as follows:
Air photos, ARE based on ground control. I'd want that ground control, and start there, with it. If it was not forthcoming, then I'd tell them they HAVE PROBLEMS!. I mean, they already do, but they are BIGGER!
IF I got ground control, then I'd resurvey the ground control. with Post Processed GPS, in STATIC MODE. (That is find the air targets, and spikes in the middle of them, and re tie them.
Then, OVERLAY and combine the easements.
Then, go and determine the best RTK control points, and Static those in.
Then, I'd start staking the RW and CHECKING into local boundaries, and I'd Live ready for the project to go from a 100k job, to a 500 k job, to get it done right. I'd tell them this up front.
N
question
So they created the mathematical description of the centerline from a photo?
Are you writing the deeds without traversing it?
question
In general we are fixing a problem of the State having no legal easement over lands of the United States. About 30 roads in all summing up to 200 miles.
The entire state was flown to 1' rez a couple years ago and that data is being used to generate the descriptions. (State contract)
Federal Highways was tasked with creating the legal descriptions / plats.
I requested the descriptions be done in State plane, tied to existing USA monuments (static GPS at the termini), and monuments set for reference.
I got state plane coords at all PC/PT (as picked from the ortho), and ties to USA monuments at termini.
I am now trying to figure out how to review all this information for correctness and make any modifications so future surveyors can recreate this thing.
> Centerline description was done by others using a rectified orthophoto
Why not fly along the alignment and throw irons out of the plane every so often?;-)
question
> About 30 roads in all summing up to 200 miles.
>
> I got state plane coords at all PC/PT (as picked from the ortho), and ties to USA monuments at termini.
>
> I am now trying to figure out how to review all this information for correctness and make any modifications so future surveyors can recreate this thing.
You might consider creating a sample subset of 20% randomly selected PC/PT points covering the entire project. Using GPS control, locate these positions on the ground and see how well they fit the center of the 'road'. Provide them improved coords if you want...make them adjust the alignment.
DDSM:beer:
Each Easement Is Separately Accountable For Accuracy
Do not attempt to hold state survey standards for a series of projects in their entirety that are subject to countless other controlling factors.
Paul in PA
