On Sun, Aug 24, 2014 at 09:18:20AM +1200, Bruce wrote:
> A bug? Depends on point of view I guess, cartesian implies no actual
> distance measured, so zero survey length, but the definition of two points
> does have some parallels with a 'shot' and hence survey length.
I don't think that is implied - it's just a different way of specifying
measurements between two points.
When we added it to Survex originally the idea was it provided a way
to specify measurements which didn't fit any of the other supported
data styles, without forcing people to invent tape/compass/clino data
from such measurements.
> I have not checked any of the other data survey formats.
> Other peoples thoughts on this?
FWIW, Survex treats cartesian data as counting in the survey length by
the same rules as other measured data styles, and nosurvey data never
counts towards the surveyed length (it's assumed to be used for things
like visual connections or other unsurveyed links like you say, and
really the clue is in the name).
I hadn't thought about something like you GPS trail example where
an instrument produces a series of absolute positions before. Perhaps a
measured version of "nosurvey" would be useful, though I'm not sure we
yet have something which can do that underground. Radiolocation could
theoretically, but practically it takes too long to set up at each
position to be a sane option for surveying a series of points along a
passage using it, unless things have evolved a lot since I was last
involved.
Cheers,
Olly
