BCRA Grades

[Martin Ellis]

Olly wrote:
>
> I take it this change isn't justified in the book?  If not, that's a
> pity.
>

There isn't a justification in the book, but the new G5 definition is
printed in bold which is why I spotted it.

Now that the grades are based on precision and not accuracy (wasn't this the
basis of the old CRG grades?) the wording needs to be changed throughout the
table so that accurate is replaced with precise. As an example the
definition of G6 is "magnetic survey that is more accurate than G5" whilst
the notes below say "A G6 survey requires the compass to be used at the
limit of possible accuracy, i.e. accurate to +/- 0.5 deg."  These should
read "magnetic survey that is more precise than G5" and "A G6 survey
requires the compass to be used at the limit of possible precision, i.e.
precise to +/- 0.5 deg."

With the new definitions a long G3 survey could be more accurate than a
short G5 survey as the errors are more likely to cancel out on the longer
survey.

Regards

Martin