We have discussed and made fun of all the bad ones.
Give me some examples of good ones. The complete "NGS OPUS Solution" report seems too much, but what part of it should be included?
Vern
> We have discussed and made fun of all the bad ones.
>
> Give me some examples of good ones. The complete "NGS OPUS Solution" report seems too much, but what part of it should be included?
>
>
> Vern
I'm not sure any of the report should be included. By plans, I take it you mean the deliverables and by derivation report, I take it you mean meta data statement. Mine goes a little something like this and is an ad-lib and compilation of many that I've seen over time.
BEARINGS are based on the Texas Coordinate System of 1983, Texas Central Zone per GPS observations. All coordinates are U.S. Survey Feet, NAD83(2011) Epoch 2010.0000 per static GPS data and an OPUS solution through the NGS website. If it's a big tract, say more than 20 acres. At the point of beginning, angle of convergence is 02°14'20" and to get geodetic bearings, rotate the bearings shown hereon/recited herein, clockwise by the angle of convergence. All distances are grid and the combined scale factor at the point of beginning is 0.9999864, and to get surface distances, divide the distances shown hereon/recited herein, by the combined scale factor. If the tract is under 20 acres. To get geodetic bearings, rotate the bearings shown hereon, clockwise, 02°14'20". All distances are grid and to get surface distances, divide the distances shown hereon/recited herein by 0.9999864.
I leave my tracts on the grid. I've used the tools in Carlson before to have it report the surface distances, but I don't like the fact that you can't have the same coordinates I report if you use surface distances, and for that reason, and the reason that I'm typically 20 miles from a zone line and less elevation, most of the time, than 500', it's very close. Shawn and J.D. Billings report surface but whenever I've chased their work, I've never had a problem going from one to the other. It's very simple with their meta-data statements.
The ones that hack me off are some that are so simplistic, that they truly don't relay what the end user needs to properly position the tract and has some ambiguity. When I first got serious about this years ago, my meta-data statement was MUCH longer and has been shorter, but I've settled on this as the equivalent of giving enough parts of a curve to check the data that is presented rather than just giving two parts, or parts that have no bearing like radial bearings to the radius point.
BEARINGS refer to the Texas Coordinate System of 1983(South Central Zone) as computed from GPS vectors.
DISTANCES are Horizontal Surface Distances in units of US Survey Feet, computed using an Average Project Combined Scale Factor of 0.999872.
Surface Distance = Grid Distance / 0.999872.
COORDINATES are in units of US Survey Feet and refer to the Texas Coordinate System of 1983(South Central Zone) obtained by connection to the National CORS network from more than four hours of L1/L2 GPS observations computed via the National Geodetic Survey's OPUS utility using rapid orbits and extended across the project via GPS vectors and conventional observations adjusted in combination. Unless otherwise indicated, coordinates are thought from analysis of variance to have uncertainties in N and E components of less than +/-1cm (standard error).
Request To Kent (RTK)
I almost started this thread with that subject because I thought you would provide a good answer. That is good for a big project that stays on SPC. What about the little lot that I set SPC on one point and the rest is ground from there?
Request To Kent (RTK)
> I almost started this thread with that subject because I thought you would provide a good answer. That is good for a big project that stays on SPC. What about the little lot that I set SPC on one point and the rest is ground from there?
Well, the advantage to using the SPCS for everything is that a surveyor is likely to do more work in the subdivision. Unless the subdivision is very large or there is a huge change in elevation across it, most likely the very same Project Average CSF that was used for the lot survey will work just fine for all of the other lots that may get surveyed in the subdivision.
By the way, let me amend the specimen note that I posted earlier to read:
>BEARINGS refer to GRID NORTH of the Texas Coordinate System of 1983(South Central Zone) as computed from GPS vectors.