?ÿ
But if true bearings and surface distances are used, then how will a closure be calculated??ÿ ??ÿ
After all that's what is most important.?ÿ
I've sure considered doing it for some larger plats. Heck a good sized subdivision would make a perfect "true" survey. You could trigger lots of checkers doing that.?ÿ
The map checkers will just have to update their software, and learn a few things....
Maybe he was referring to the cost of his receiver.
?ÿ
If a plat says:
"Basis of bearings is true north"
It means that at SOME point, either on, or near the survey, that either a sunshot, celestial observation, or gps was used, to determine geodetic north. Then a RECTANGULAR coord survey was performed.
These things are "understood", not spelled out. I know it is not "proper", but it is common.
Back in the day, just doing a sunshot, to determine geodetic north, was considered "way beyond the call of duty". Some still feel that way. Others called it "solar north". It was geodetic, at ONE POINT of the survey. Or, someplace near, or sorta nearby.
N
By the way....
Javad has got a tool now, called J-mate. It's a mini, camera based, robot, that is integrated with gps.
With it, you COULD do a solar observation, without a backsite.
It has a routine, with solar filter, to roboticly perform a solar observation, for a backsite, if the sun is viable. It has all the ephemeris, time, corrections, and all. With it, you could do what the original post said...
N
By the way....
Javad has got a tool now, called J-mate. It's a mini, camera based, robot, that is integrated with gps.
With it, you COULD do a solar observation, without a backsite.
It has a routine, with solar filter, to roboticly perform a solar observation, for a backsite, if the sun is viable. It has all the ephemeris, time, corrections, and all. With it, you could do what the original post said...
N
Maybe this fellow was a beta tester back in 2014... ??ÿ
If a plat says:
"Basis of bearings is true north"
It means that at SOME point, either on, or near the survey, that either a sunshot, celestial observation, or gps was used, to determine geodetic north. Then a RECTANGULAR coord survey was performed.
These things are "understood", not spelled out. I know it is not "proper", but it is common.
Back in the day, just doing a sunshot, to determine geodetic north, was considered "way beyond the call of duty". Some still feel that way. Others called it "solar north". It was geodetic, at ONE POINT of the survey. Or, someplace near, or sorta nearby.
N
Astronomic observations produce astronomic north, which can then be corrected to geodetic north by applying the Laplace correction. Wherever the slope of the geoid is near zero, True North = Astronomic North = Geodetic North.
In fairness to Nate, I would imagine that the Laplace correction in the great majority of Arkansas is near 0.0".?ÿ In the Foothills west of Denver where I work the Laplace correction can approach 50" (and, yes I still do solars).