Self-looping shots in Survex

[Olly Betts]

On Sat, Feb 15, 2020 at 10:11:08PM -0500, Luc Le Blanc wrote:
> Perusing the Survex doc, I can't find whether self-looping (from = to
> station) are now supported in Survex.

No, and deliberately not - there's even a testcase in the testsuite to
check they give an error:

$ cavern tests/self_loop.svx
[...]
tests/self_loop.svx:5: error: Survey leg with same station (“2”) at both
ends - typing error?
 2 2  1 0 0

Measuring from a point to itself doesn't really make sense, and presumably
indicates a recording or transcription error.

> Auriga uses them to store GPS
> positions, and I used to export them to Survex as null-length splay
> measures, but it gets more complicated to import them now that splay
> measures can be appended to regular shots without the explicit 'splay'
> command.

Use *fix for GPS points.  That's much better than trying to hack them in
as weird fake legs.

Cheers,
    Olly