<div dir="ltr"><div class="gmail_default" style="font-family:tahoma,sans-serif">Hello,</div><div class="gmail_default" style="font-family:tahoma,sans-serif"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">it is already fixed in the latest release and therion is parsing survex .err file for loop errors and outputs sigmas to .3d file. You may compare data.3d generated by survex (in thTMPDIR when -d is used) and therion generated .3d file, that they are equal when colored by error.</div><div class="gmail_default" style="font-family:tahoma,sans-serif"><br></div><div class="gmail_default" style="font-family:tahoma,sans-serif">S.</div><div class="gmail_extra"><br><div class="gmail_quote">On 3 April 2017 at 03:49, Olly Betts via Therion <span dir="ltr"><<a href="mailto:therion@speleo.sk" target="_blank">therion@speleo.sk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>On Sat, Apr 01, 2017 at 09:10:02PM +1300, Bruce Mutton via Therion wrote:<br>
> The new capability of exporting loop closure information to 3d format is<br>
> helping to identify the bad loops on our surveys.<br>
><br>
> Very nice.<br>
><br>
> However the scalebar at the top right seems to be locked into a range of 0.0<br>
> to 12.0 (%) error.<br>
<br>
</span>Aven's error scale isn't in %, but rather in "sigmas" - i.e. it's how many<br>
times the expected error the observed error is. Assuming normal distribution<br>
of errors (which sums of random errors will tend towards) anything more than<br>
3 is only 0.3% likely by random errors, so highly suspect:<br>
<br>
<a href="https://en.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule" rel="noreferrer" target="_blank">https://en.wikipedia.org/wiki/<wbr>68%E2%80%9395%E2%80%9399.7_rul<wbr>e</a><br>
<br>
If what Stacho said back in February is still true, therion outputs the<br>
wrong data in this field in the 3d file, so you actually see "2 * relative<br>
error of a loop" there, by which I think he means percentage misclosure.<br>
<br>
But as I said at the time, percentage misclosure isn't really a useful<br>
measure of loop quality because the threshold of what is reasonable<br>
varies with the length of the loop:<br>
<br>
<a href="https://mailman.speleo.sk/pipermail/therion/2017-February/006300.html" rel="noreferrer" target="_blank">https://mailman.speleo.sk/pipe<wbr>rmail/therion/2017-February/<wbr>006300.html</a><br>
<span><br>
> This is OK for our really nasty loop closures; the maps look suitably<br>
> colourful, but some of our more recent cave surveys don't have error much<br>
> more than 1.5%, so the picture is kind of shades of blue, as below. It<br>
> doesn't help with visualising the relative quality of the loops.<br>
<br>
</span>Unless Stacho has since fixed this, you're actually seeing 0-6% there<br>
currently.<br>
<span><br>
> Would it be possible to change the default scalebar to something like 0.0 to<br>
> 2.0, with the upper limit stepping upwards to suit the data, if there are<br>
> larger loop errors?<br>
<br>
</span>I'd much rather we fixed therion to export the correct error information.<br>
Trying to colour based on percentage error just seems to be fundamentally<br>
a less helpful approach.<br>
<br>
Also, not varying the colours for a particular number of sigmas depending on<br>
how bad the data is was a deliberate choice. 2 sigmas is no better or worse<br>
just because someone blundered a survey elsewhere. And if data is surveyed to<br>
a lower quality the grades should be set appropriately to reflect that.<br>
<div class="m_5712684655798250755HOEnZb"><div class="m_5712684655798250755h5"><br>
Cheers,<br>
Olly<br>
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</div></div></blockquote></div><br></div></div>