Maybe not a 10" Total Station
> > Still need advice on where to set the "Angle", "Direction", and "Azimuth/Bearing" settings for the instrument in Starnet. They're currently at 10".
>
> What one really should do is test the instrument to see what the actual uncertainty of a direction taken as the mean of two faces really is. It is very simple to do and may well be considerably better than a standard error of +/-10". Just because the display rounds to the nearest 10" doesn't mean that 10" is the uncertainty of a direction.
>
> For example, a direction to a target Face Lt that is displayed as 20°25'40" may be in the range of 20°25'35" to 20°25'45" if the rounding is good. That is a range of +/-5" from the value displayed and there would be a 68% chance that the value displayed was within 0.68 x 5" = 3.5", considering rounding error alone.
Thanks. I'll do that. The Starnet manual suggests using the the 'Direction", or pointing standing error times the square root of 2 for the "Angle" number, but I don't really understand the difference between "Direction" and "Azimuth/Bearing". There's nothing on it in the Starnet manual.
Maybe not a 10" Total Station
> The Starnet manual suggests using the the 'Direction", or pointing standing error times the square root of 2 for the "Angle" number, but I don't really understand the difference between "Direction" and "Azimuth/Bearing". There's nothing on it in the Starnet manual.
It sounds as if perhaps it would be a good idea if you described how you're using the instrument to measure angles. In ordinary practice with an electronic total station, angles are obtained by subtracting the directions observed to the objects, which is why the uncertainty of an angle is estimated as SQRT(2) times the s.e. of a direction.
Azimuth/Bearing, of course, refers to a direction taken with respect to North.
Maybe not a 10" Total Station
I think Kent has a ten gallon brain under that hat.
Maybe not a 10" Total Station
> > The Starnet manual suggests using the the 'Direction", or pointing standing error times the square root of 2 for the "Angle" number, but I don't really understand the difference between "Direction" and "Azimuth/Bearing". There's nothing on it in the Starnet manual.
>
> It sounds as if perhaps it would be a good idea if you described how you're using the instrument to measure angles. In ordinary practice with an electronic total station, angles are obtained by subtracting the directions observed to the objects, which is why the uncertainty of an angle is estimated as SQRT(2) times the s.e. of a direction.
>
> Azimuth/Bearing, of course, refers to a direction taken with respect to North.
I'm measuring angles exactly as you describe, and as the Starnet manual assumes. Point, Zero, Turn, Measure (then either hold and repeat, or plunge and repeat, or both).
But there's a "Standard Error" number they expect you to fill in for "Azimuth/Bearing". Do some total stations have electronic compasses built in, and therefore would require you to enter a number representing the standard error of such readings? If that's the case, my assumption would be that for a gun without such capability, one would leave the number close to zero (it won't let you enter zero).
Maybe not a 10" Total Station
I'm with Kent on this one. My guess is somebody is out fishing for answers they don't even understand the question about. Sad.
I've played with "starnet". Yea, it's cool and gives you warm & fuzzies when you just change a setting here and there. Not much different than any other program. I wouldn't waste 10 cents on it though to buy it.
At the end of the day, you still have to get the points in the right spot on the ground. Ask the lawyer. Can I retire soon....
Maybe not a 10" Total Station
:good:
Maybe not a 10" Total Station
> I'm measuring angles exactly as you describe, and as the Starnet manual assumes. Point, Zero, Turn, Measure (then either hold and repeat, or plunge and repeat, or both).
Actually, the only assumption made by Star*Net about how angles are measured is that they are free of systematic errors and are made by a uniform process that can be characterized by the standard error of a direction (ordinarily taken as the mean of F Lt and F Rt) or by the standard error of an angle (also ordinarily taken as the mean of F Lt and F Rt to minimize certain systematic errors).
So, the first thing to do is to revisit your angle measuring technique to find one that meets the above criteria.
Maybe not a 10" Total Station
>But there's a "Standard Error" number [Star*Net] expect you to fill in for "Azimuth/Bearing".
You aren't measuring any azimuths or bearings. The only one you have is the fixed bearing of one line to orient your whole figure. Until you actually measure azimuths via GPS or astronomical methods, you could ignore that setting.
