Just checking to see what everyone does with this type of survey: Two Static GPS points at either end of a 2900 ft open (link) traverse(500 to 503). Misclosure of 0.35 at 502.
This is simply the ground distance longer than the grid. Bring ground to grid and adjust (1 to 300,000 precision). Question: how do you handle the fact that all boundary location must be located on ground? Also, since I was running due north (approximately) arc-to-chord was not performed. I usually do arc-to-chord on long east-west surveys.
We're at sea level, so the difference between grid and ground is very rarely enough to matter. But if I did need ground coordinates from my GPS, there's a very simple routine in Trimble Access to calculate them.
> Just checking to see what everyone does with this type of survey: Two Static GPS points at either end of a 2900 ft open (link) traverse(500 to 503). Misclosure of 0.35 at 502.
> This is simply the ground distance longer than the grid. Bring ground to grid and adjust (1 to 300,000 precision). Question: how do you handle the fact that all boundary location must be located on ground? Also, since I was running due north (approximately) arc-to-chord was not performed. I usually do arc-to-chord on long east-west surveys.
We bring everything to ground, and use localization sets (calibrations) to scale/rotate RTK to our control.
With Survey Controller I have two files setup, one for each of the two zones I usually work in using State Plane Coordinates. I open one of those two, which ever zone I'm in, and then start a new job. The zone will transfer to the new job until someone changes it. I change the setup for coordinates to Ground(keyed in scale factor) and right below it under Ground scale factor I enter a number that is 1/combined scale factor that you would find on an opus return. TxDot published a list for all counties for a county wide scale factor or surface adjustment factor as they call it but they don't always use it. Sometimes it is a factor calculated just for that job and sometimes it is 1.0000 or actual grid. The trick is to setup the original two jobs so that the scaling is from 0,0.
James
> We bring everything to ground, and use localization sets (calibrations) to scale/rotate RTK to our control.
That's pretty much what I do. I'm tending to only do control with my GPS, adjusted to ground when I'm happy with what I see. (most of my work is elevations over 3,000 ft and it will make a difference) I use my robot to set property corners. I've got pretty good confidence in the procedure, and being an old timer I do like to "walk the land" that I'm surveying if for no other reason than to look for something I may have missed (encroachment??), and I like to walk - plus certainly need the exercise.
I will show my combined scale factor and pertinent data on maps when I think it's appropriate, but at the end of the day we all have to get to ground. Ask any contractor or lawyer.
When I see maps that are "grid", the client has no clue what that means. We all know sea level isn't flat, as the geoid gets tweeked every couple years, and what the heck good is ellipsoidal height to your client? I suppose scope of contract does come into play too, not to mention local regulations where the reviewer has no clue either?
$0.02
:gammon:
:gammon: 
O.S.Adams 1935
http://docs.lib.noaa.gov/rescue/journals/geodetic_letter/QB275G431937Jan.pdf
You Do Understand GPS Gives You Ground Vectors?
Your post processed GPS vectors are slope distances from one XYZ point to a second XYZ point.
Simply use the ellipsoid elevation and Pythagoreans theorem to adjust to a horizontal traverse distance. Simplest quickest check you can do. No scale factor required.
Paul in PA
> Question: how do you handle the fact that all boundary location must be located on ground?
Simple enough.
1) Adjust 3D traverse in SPCS in Star*Net, which makes rigorous reductions of measured distances to grid.
2) Choose average CSF even for projects of 1000 acres or more across which the CSF shouldn't differ by more than about 2 or 3 ppm from the average unless you're in the mountains.
3) Use average CSF for boundary calculations by just entering it into software to be automatically applied to distances input.
4) Calculate state plane coordinates of markers to be set.
5) Plug average CSF into data collector and go set markers at previously calculated SPCS coordinates.
6) Get as-set ties to markers and add those to network adjustment.
7) Calculate as-set coordinates in Star*Net to compare to target or design coordinates.
8) Live happily ever after with actual as-set coordinates and elevations of markers in records in highly usable form
And Kent's way is how you work in SPC.
For the record, I have no problem with someone choosing to do a job in SPC. I even see how it could be superior.
So Kent's solution has a lot of merit.
I am curious if you would advocate running a full topo/boundary of 160 acres through StarNet (Maybe 10000 points with road frontage, etc.)
Part of the issue the OP will probably face is that there may be engineering plans, and he has to play nicely with them.
Thanks to everyone who replied. Got some great information.
Linebender...
NEVER EVER EVER...!!!
Linebender...
> NEVER EVER EVER...!!!
I don't suppose it ever will if it hasn't in the 80 years since the discussion began. I just found it interesting that 80 years ago there was a Mr. G.