Survex digest, Vol 1 #136 - 3 msgs

Richard Knapp
Wed, 01 Aug 2001 11:29:58 -0400 (EDT)

>From: Mike Lake <>


>One problem I see is that there seems to be no concensus on the format of
>LRUD data. Some users have just one set of 4 LRUD data points per station
>others have two sets; one set "looking into the station" and another set
>"looking out of the station". 

Not to mention the lack of a frame of reference. Yes, LRUD are dependant on a shot but there are three ways they can 
be taken:

	- perpendicular to next;
	- perpendicular to last;
	- average between last and next.

CRF used to "require" dims at both TO and FROM stations for the yet to be developed software for passage modeling 
(this was back in the 70s and 80s). Of course no one recorded the data and if it was, it was never used.

Theoretically, there is no reason why the dimesions taken are limited to just LRUDs. The work Julian Todd did on Tunnel 
with respect to cross-sections provides more dimension capability; LRUDs are just convenient sub-set.

CaveXML has had some good options presented on this track.

	- Richard Knapp

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