Re: [Therion] Aven colour by loop error

[Bruce Mutton via Therion]

Nice, thank you all for all the hard work that has gone into the new 5.4.0

It works!

Sadly many of my projects still have bright red 12 standard deviation loop 
errors!

Perhaps time to lower the survey grade claims made in the .th files!

Bruce

 

From: Therion [mailto:therion-boun...@speleo.sk] On Behalf Of Stacho Mudrak via 
Therion
Sent: Wednesday, 5 April 2017 11:39 PM
To: List for Therion users <therion@speleo.sk>
Cc: Stacho Mudrak <li...@group-s.sk>
Subject: Re: [Therion] Aven colour by loop error

 

​Hello,

 

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.

 

S.

 

 

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Re: [Therion] Aven colour by loop error

[Stacho Mudrak via Therion]

​Hello,

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.

S.

On 3 April 2017 at 03:49, Olly Betts via Therion  wrote:

> On Sat, Apr 01, 2017 at 09:10:02PM +1300, Bruce Mutton via Therion wrote:
> > The new capability of exporting loop closure information to 3d format is
> > helping to identify the bad loops on our surveys.
> >
> > Very nice.
> >
> > However the scalebar at the top right seems to be locked into a range of
> 0.0
> > to 12.0 (%) error.
>
> Aven's error scale isn't in %, but rather in "sigmas" - i.e. it's how many
> times the expected error the observed error is.  Assuming normal
> distribution
> of errors (which sums of random errors will tend towards) anything more
> than
> 3 is only 0.3% likely by random errors, so highly suspect:
>
> https://en.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule
>
> If what Stacho said back in February is still true, therion outputs the
> wrong data in this field in the 3d file, so you actually see "2 * relative
> error of a loop" there, by which I think he means percentage misclosure.
>
> But as I said at the time, percentage misclosure isn't really a useful
> measure of loop quality because the threshold of what is reasonable
> varies with the length of the loop:
>
> https://mailman.speleo.sk/pipermail/therion/2017-February/006300.html
>
> > This is OK for our really nasty loop closures; the maps look suitably
> > colourful, but some of our more recent cave surveys don't have error much
> > more than 1.5%, so the picture is kind of shades of blue, as below.  It
> > doesn't help with visualising the relative quality of the loops.
>
> Unless Stacho has since fixed this, you're actually seeing 0-6% there
> currently.
>
> > Would it be possible to change the default scalebar to something like
> 0.0 to
> > 2.0, with the upper limit stepping upwards to suit the data, if there are
> > larger loop errors?
>
> I'd much rather we fixed therion to export the correct error information.
> Trying to colour based on percentage error just seems to be fundamentally
> a less helpful approach.
>
> Also, not varying the colours for a particular number of sigmas depending
> on
> how bad the data is was a deliberate choice.  2 sigmas is no better or
> worse
> just because someone blundered a survey elsewhere.  And if data is
> surveyed to
> a lower quality the grades should be set appropriately to reflect that.
>
> Cheers,
> Olly
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[Therion] Aven colour by loop error

[Bruce Mutton via Therion]

The new capability of exporting loop closure information to 3d format is
helping to identify the bad loops on our surveys.

Very nice.

However the scalebar at the top right seems to be locked into a range of 0.0
to 12.0 (%) error.

This is OK for our really nasty loop closures; the maps look suitably
colourful, but some of our more recent cave surveys don't have error much
more than 1.5%, so the picture is kind of shades of blue, as below.  It
doesn't help with visualising the relative quality of the loops.

 

Would it be possible to change the default scalebar to something like 0.0 to
2.0, with the upper limit stepping upwards to suit the data, if there are
larger loop errors?

 

Bruce

 



 

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Re: [Therion] Aven colour by loop error

[Bruce Mutton via Therion]

Martin

You are right, and I do use the workflow that you describe.

 

However if one needs a very quick and very clear macro representation of how
good the loop closures are, or if you want to compare projects.  Or if you
inherit or need to debug someone else's project, then the methods available
in Therion are tedious.

 

Aven provides a very nice way to make these macro comparisons (once Therion
can export the data).

 

Bruce

PS: I am thinking mainly of centrelines here, scraps are not so relevant.

 

From: Therion [mailto:therion-boun...@speleo.sk] On Behalf Of Martin Sluka
via Therion
Sent: Friday, 24 February 2017 9:34 AM
To: List for Therion users <therion@speleo.sk>
Cc: Martin Sluka <martinsl...@mac.com>
Subject: Re: [Therion] Aven colour by loop error

 

 


On Feb 23, 2017, at 08:06 PM, Bruce Mutton via Therion <therion@speleo.sk
<mailto:therion@speleo.sk> > wrote:

Martin

The Therion debug feature is useful, but I would suggest that it is for
micro interrogation of at most a few scraps at a time, and not for quickly
identifying the macro loop error health of a project.

Typos like the one you describe would not be evident from scrap distortions,
at least in my case, as (in the old days of manual surveying with compass
and book) the scraps would be drawn using the erroneous data, so no
distortion mismatch between centreline and scrap would be flagged by
Therion.  Would only be found by the person drawing noticing that something
looked out of proportion.

 

It is the question of your workflow. 

I check each scrap individually, I check each map, each bigger map etc. I
check it after each equate command (new loop closure), etc. I'm not sure if
the best way is to start from huge system down to individual scraps.

 

Martin 

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Re: [Therion] Aven colour by loop error

[Olly Betts via Therion]

On Thu, Feb 23, 2017 at 10:00:35AM +0100, Martin Sluka via Therion wrote:
> 
> > 23. 2. 2017 v 3:08, Olly Betts via Therion :
> > 
> > I've done the armchair equivalent and used Aven's error colouring to
> > successfully find mis-ties, reversed legs, etc.
> 
> You will find them by drawing scraps in xtherion with "debug on“ option in
> thconfig immediately. Typos too - like 1.23/12.3 m length. Idea of scraps and
> maps is the most important part of Therion.

OK, but Stacho's question was about the error measures in aven...

Cheers,
Olly
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Re: [Therion] Aven colour by loop error

[Martin Sluka via Therion]

By the way, is it possible to create a Therion debug with the black, yellow and orange debug features, without the ‘first’, ‘second’ and ‘scrap-names’?You may change it by scale and base-scale m

error_visualisation_data_ok_walls_500.pdf
Description: Adobe PDF document


error_visualisation_data_ok_walls_500-50.pdf
Description: Adobe PDF document


error_visualisation_data_ok_walls_50.pdf
Description: Adobe PDF document
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Re: [Therion] Aven colour by loop error

[Martin Sluka via Therion]

On Feb 23, 2017, at 08:06 PM, Bruce Mutton via Therion  
wrote:

Martin
The Therion debug feature is useful, but I would suggest that it is for micro 
interrogation of at most a few scraps at a time, and not for quickly 
identifying the macro loop error health of a project.
Typos like the one you describe would not be evident from scrap distortions, at 
least in my case, as (in the old days of manual surveying with compass and 
book) the scraps would be drawn using the erroneous data, so no distortion 
mismatch between centreline and scrap would be flagged by Therion.  Would only 
be found by the person drawing noticing that something looked out of proportion.

It is the question of your workflow. 


I check each scrap individually, I check each map, each bigger map etc. I check 
it after each equate command (new loop closure), etc. I'm not sure if the best 
way is to start from huge system down to individual scraps.

Martin 
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Re: [Therion] Aven colour by loop error

[Martin Sluka via Therion]

> 23. 2. 2017 v 3:08, Olly Betts via Therion :
> 
> I've done the armchair equivalent and used Aven's error colouring to
> successfully find mis-ties, reversed legs, etc.
> 

You will find them by drawing scraps in xtherion with "debug on“ option in 
thconfig immediately. Typos too - like 1.23/12.3 m length. Idea of scraps and 
maps is the most important part of Therion.

m.s.
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Re: [Therion] Aven colour by loop error

[Olly Betts via Therion]

On Thu, Feb 23, 2017 at 12:08:09AM +0100, Stacho Mudrak via Therion wrote:
> Hi, I agree with Bruce, that it is really a very useful feature. I have
> just pushed it on GitHub (see commit 2ebc7ed).
> 
> The only problem is, that survex calculates error which "is the ratio of
> the observed misclosure to the theoretical one". I have implemented more
> simple export (it was much easier), currently therion .3d export contains
> error equal to 2 * relative error of a loop. (because of 0-12 aven fixed
> error scale). It should be possible to extract survex relative error from
> either thTMPDIR/data.err or data.3d file, but it will take some time.

I'd definitely use the .3d file (no rounding, and a file format that's
intended for machine parsing).

> But when I compared 3D files with relative loop error and error with survex
> ratio, I received two quite different pictures. Are these two measures not
> comparable? Is a relative error of a loop useless number?

tl;dr: No and yes!

By "relative error of a loop" I'm assuming you mean "misclosure / length
of traverse * 100%".  If so that's not really a useful measure, though
at least historically it's been a fairly popular one, I suspect because
it's an obvious one to calculate.

The problem with it is that what's a "good" value depends on the length
of the traverse.  For random errors, the squares of the errors add, so a
traverse which is 100 times as long would be expected to only have 10
times the error, which means the relative error would be expected to be
10/100 = 1/10 as much.

As well as not providing a reliable measure of the random error, a
blunder in a long traverse will tend to be smoothed out in the relative
error, as it gets divided by the length of the traverse.

Observed error divided by theoretical error should be agnostic to length
of traverse.  It's simply telling you which traverses don't seem to be
surveyed to the accuracy that was claimed.

> Has anybody tried to go to a cave and resurvey "red shots", whether
> they are really so bad?

I've done the armchair equivalent and used Aven's error colouring to
successfully find mis-ties, reversed legs, etc.

Cheers,
Olly
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Re: [Therion] Aven colour by loop error

[Stacho Mudrak via Therion]

Hi, I agree with Bruce, that it is really a very useful feature. I have
just pushed it on GitHub (see commit 2ebc7ed).

The only problem is, that survex calculates error which "is the ratio of
the observed misclosure to the theoretical one". I have implemented more
simple export (it was much easier), currently therion .3d export contains
error equal to 2 * relative error of a loop. (because of 0-12 aven fixed
error scale). It should be possible to extract survex relative error from
either thTMPDIR/data.err or data.3d file, but it will take some time.

But when I compared 3D files with relative loop error and error with survex
ratio, I received two quite different pictures. Are these two measures not
comparable? Is a relative error of a loop useless number? Has anybody tried
to go to a cave and resurvey "red shots", whether they are really so bad?

S.



On 22 February 2017 at 23:20, Olly Betts via Therion 
wrote:

> On Wed, Feb 22, 2017 at 09:34:03PM +, Footleg via Therion wrote:
> > Therion strips most of the data apart from staions and legs out of 3D
> files
> > it generates. Colour by error and by date are not possible because that
> > information is not in the 3D files generated from a Therion project.
> > Entrances are lost too. One of the reasons I plan to add Therion to
> Survex
> > conversion into my cave converter program (when time permits).
>
> Therion-generated .3d files now[*] contain date and coordinate system
> information, thanks to a patch from Vlad:
>
> https://github.com/therion/therion/commit/43e6630e3109196d2c
> 251f05e52c2663496419d9
>
> [*] This isn't in a released version of therion yet, but I'm guessing
> there's likely to be a new release soon as it's been years since 5.3.16
> and a lot of useful stuff has been merged recently.
>
> Cheers,
> Olly
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Re: [Therion] Aven colour by loop error

[Olly Betts via Therion]

On Wed, Feb 22, 2017 at 09:34:03PM +, Footleg via Therion wrote:
> Therion strips most of the data apart from staions and legs out of 3D files
> it generates. Colour by error and by date are not possible because that
> information is not in the 3D files generated from a Therion project.
> Entrances are lost too. One of the reasons I plan to add Therion to Survex
> conversion into my cave converter program (when time permits).

Therion-generated .3d files now[*] contain date and coordinate system
information, thanks to a patch from Vlad:

https://github.com/therion/therion/commit/43e6630e3109196d2c251f05e52c2663496419d9

[*] This isn't in a released version of therion yet, but I'm guessing
there's likely to be a new release soon as it's been years since 5.3.16
and a lot of useful stuff has been merged recently.

Cheers,
Olly
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Re: [Therion] Aven colour by loop error

[Benedikt Hallinger via Therion]

I am able to export fixed stations and entrances with therion 5.3.15.
They are nicely visible once the button is activated in the aven viewer.


Am 2017-02-22 23:34, schrieb Footleg via Therion:
Therion strips most of the data apart from staions and legs out of 3D 
files it generates. Colour by error and by date are not possible because 
that information is not in the 3D files generated from a Therion project. 
Entrances are lost too. One of the reasons I plan to add Therion to Survex 
conversion into my cave converter program (when time permits).


Footleg

On Wed, Feb 22, 2017 at 6:46 PM Bruce Mutton via Therion 
<therion@speleo.sk [7]> wrote:


I really need it!  It seems the interface is and data there, just need 
the two to be introduced to each other.


Therion debug does not show the loop errors as far as I can tell, only 
the single largest error, and scrap distortions.


Therion.log lists all the errors, but what I need is this information in 
graphical form.


 

Bruce

 

FROM: Therion [mailto:therion-boun...@speleo.sk [2]] ON BEHALF OF Martin 
Sluka via Therion

SENT: Wednesday, 22 February 2017 9:45 PM
TO: List for Therion users <therion@speleo.sk [3]>
CC: Martin Sluka <martinsl...@mac.com [4]>
SUBJECT: Re: [Therion] Aven colour by loop error

 

 


22. 2. 2017 v 9:05, Bruce Mutton via Therion <therion@speleo.sk [1]>:

 

Is ‘colour by loop error’ something that could readily be added to the 
Therion export?


 


 

Do you really need it? There is „debug on“ option in thconfig, which will 
produce very clear visualization of the biggest error in exported map.


 

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Re: [Therion] Aven colour by loop error

[Bruce Mutton via Therion]

I really need it!  It seems the interface is and data there, just need the two 
to be introduced to each other.

Therion debug does not show the loop errors as far as I can tell, only the 
single largest error, and scrap distortions.

Therion.log lists all the errors, but what I need is this information in 
graphical form.

 

Bruce

 

From: Therion [mailto:therion-boun...@speleo.sk] On Behalf Of Martin Sluka via 
Therion
Sent: Wednesday, 22 February 2017 9:45 PM
To: List for Therion users <therion@speleo.sk>
Cc: Martin Sluka <martinsl...@mac.com>
Subject: Re: [Therion] Aven colour by loop error

 

 

22. 2. 2017 v 9:05, Bruce Mutton via Therion <therion@speleo.sk 
<mailto:therion@speleo.sk> >:

 

Is ‘colour by loop error’ something that could readily be added to the Therion 
export?

 

 

Do you really need it? There is „debug on“ option in thconfig, which will 
produce very clear visualization of the biggest error in exported map.

 

m.s.

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Re: [Therion] Aven colour by loop error

[Martin Sluka via Therion]

> 22. 2. 2017 v 9:05, Bruce Mutton via Therion :
> 
> Is ‘colour by loop error’ something that could readily be added to the 
> Therion export?
> 

Do you really need it? There is „debug on“ option in thconfig, which will 
produce very clear visualization of the biggest error in exported map.

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