BCRA Grade 5

[P A Hill & E V Goodall]

Wookey wrote:
>>I was
>>not able to find any survey where the surveyors 
>>tried to ascertain the accuracy of their measurements
 >
> I don't think that's true bob. I'm sure there have been efforts to quantify
> the accuracy of surveys. 

But not by the people who label their survey "Grade 5" before they know 
anything about its actual accuracy.  Claiming you know the accuracy without 
having something to compare it to is meaningless.  Talking about precision 
at least reflects the real world of those who produced the survey.

But, I don't think the simplistic term "Compass, Tape, and Climometer 
survey" captures the differences in precision or accuracy between many surveys.

> People are slightly more discerning than that. They call a CC&T survey that
> they took reasonable care over a grade 5 survey. One they took little care
> over (or used inferior equipment) they call grade 3, or maybe 4 if they
> felt it was somewhere between.

Those do sound like precision and not accuracy, I can understand the change.

[...]
>>System from a failed attempt to quantify the accuracy
>>to jargon for the sake of jargon.
> 
> However this revision does bring things more in line with practice so I do
> think that's an improvement, and not just 'jargon for the sake of jargon'.

I'd certainly agree with Wookey on that one, even if they are only a rough 
ranking.  Something that lists reading precision of clino., compass and 
tape, plus station position precision would probably cover many more cases 
  better and might be more useful to some mathematician some day than a 
simple 1 dimensional system that only hints at what the values are.

-Paul