Do you use that only to record data, or for stakeout, too??ÿ ("East a thousand of a second!")
It's the same as using state plane. East .02' except it is geodetic east and the .02 doesnt need a scale factor. Although, much to the chagrin of my assistants, I prefer meters in the field.
Would not?ÿ .02' in lat/long be an ellipsoid distance? Meaning it would require an elevation scale factor?
I like the idea, just wondering.
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Well, if using a total station no scaling is required. If using GPS you are not using the raw vector distance, if that's what you mean. The difference between state plane scaled to ground and the geodetic ground distance is that the state plane distance depends on the choices made when calculating the scale factor. If the choices made were good, and the site is small and flat, everyone should be able to match. Otherwise, you can only match the previous surveyor?ÿif you have his/her metadata, and even then it won't be the actual ground distance. Geodetic ground distance only depends on the GPS vector and the measured elevation of the end lines.?ÿWithout a blunder everyone will?ÿmatch?ÿwithout any extra information.
The?ÿbiggest downside is explaining to other surveyors (and GIS people) why your survey doesn't close when they try to draw it out on a plane.
I have found that when using TS with GPS it is best to select Earth Curvature as a part of the user experience.
I still utilize both systems.
For the past six years, everything is in State Plane Coordinates for initial work.?ÿ I do a lot of GPS rural surveys in Northeast Mississippi, and it really does help to have the USPLSS ties in the SPCS.?ÿ When I get through with the preliminary?ÿsurvey, I use Survey Pro to project to a local coordinate system 10,000/10,000 using ground distances.?ÿ I then use the convergence angle and rotate to geodetic north.?ÿ I am working near the CM of the local zone, so my CA typically varies around plus or minus about 9 minutes?ÿ ?ÿI am also working under the assumption that almost all of the previous surveys have utilized true north as determined by some method or means, and I need to retrace those as best I can, even the USPLSS lines. At least, this method narrows down to where I need to look for established corners. Deed plots can be overlaid on common points, and rotated/matched to the best fit, and the new survey corners and boundary can be worked out.?ÿ I then rotate back to grid?ÿnorth, upload the coordinates into Survey Pro, and go find or set the corners.?ÿ All data collected after the initial survey will be local/State Plane, and can be used "down the road."?ÿ If I happen to be near an old survey of mine, I simply import the coordinates, tie to some of my old control points or corners set, and match up as best I can by?ÿusing?ÿthe mapping plane ground best fit function.?ÿ I can then do stake-out to either get good coordinates or confirm the coordinates on critical points.?ÿ All of my?ÿfinal data is stored in the SPCS, and is "re-usable."?ÿ For ALTA?ÿ and high-class surveys, I create one initial point and one backsight point using GPS, then create the mapping plane ground on a local coordinate system.?ÿ I then switch to a total station, and Survey Pro will collect data in the local system with the ability to project to the SPCS if needed.?ÿ