UIS grades - update

[Andy Waddington on Survey stuff]

Wookey said

> I could probably find when they [the original CRG grades] were published
> with a bit of effort

Dave Irwin's "Presentation of Cave Surveys" in Trans CRGofGB Vol 12 No. 3 pp
155-164, July 1970 (the report on the Symposium on Cave Surveying held in
March 1970 in Leicester), refers to "a nationally agreed standard, perhaps a
very modified version of the already published CRG proposals (Butcher &
Railton, 1966)"

That reference is to

Butcher, A.L. & Railton, C.L.  1966, "Cave Surveying",
Transactions of the Cave Research Group of Great Britain,
Volume 8 number 2 (37pp)

which unfortunately, I don't have to hand, but the date is about right
for the first proposals, and Dave Irwin, writing in mid-1970, seemed
not to be aware of any more recent version at that time.

Dave's article seems to be the source of the idea that CRG grade 4 was
of very little use, as it didn't need a clinometer, without which, any
improvement in compass or tape accuracy over grade 3 was fairly pointless.

The later proposals (CRG 1973) were referred to by Bryan Ellis himself in
his letter to Compass Points 16:

... they would have found that it was first published in 'CRG Newsletter',
No. 132, pp 15-17 (Jan 1973) and that it appeared above my name. The wording
was changed slightly when first published by BCRA, which was in 'Surveying
Caves'.

Bryan's letter was in response to an increasingly pedantic discussion of
what those grades were actually meant to mean (cave survey software authors
want definitions usable in a statistical sense to make closure algorithms
work, but the definitions were never couched in those terms). Anyone
thinking about these grades could do worse than re-read that letter in:

Compass Points 16 June 1997

grrrr. the html versions no longer have actual page numbers I can quote
(and the date of the issue is extremely well-hidden in a graphic, mutter...
my own *** fault, too )-:
which is probably still on the web at

http://www.chaos.org.uk/survex/cp/cp16/cpoint16.htm#let1

(it's the second of the two numbered sections of Bryan's letter)

Andy