[Therion] ***UNCHECKED*** Re: RE: scrap without stations keeps the original sketch in Topodroid

[Stacho Mudrak]

Hi Omri,

the problem is, that stations from pocket-topo XVI file are positioned
differently than the final position calculated after loop closure.
Therefore the problem with distortions. Your loop has a relatively large
error (9%) and it is vertical one - therefore X-Y position of points is
changed significantly.

I would suggest using just two stations in your 15X scrap for calibration
(those, that are closest to the horizontal level of this section - e.g.
1_15, 1_16, 1_18) and let therion to plot other stations in this scrap
automatically (using scrap option -stations [1_9 1_10 1_11 1_12 1_13 1_14]).

S.

‪On Mon, 7 Oct 2019 at 18:30, ‫עמרי גסטר‬‎ <omrigas at gmail.com> wrote:‬

> Here is an example of what I mean:
>
> the cave I'll show is a pit and I made plan sketches as a horizontal
> sections. The extended profile turned out good.
> one of the plan sketches is distorted as you can see here:
>
> [image: image.png]
>
>
> The original scrap is  Kimron-1_15Xp, the new scrap is  scrap26,
> so, I moved all the map elements except the stations, so now my scrap look
> like this ( the stations still exists in the  .th file):
>
> scrap Kimron-1_15Xp -projection plan -scale [0 0 20 0 0 0 1 0 m]
>
> point 146.75 -130.52 station -name "1_9"
> point 162.64 -129.64 station -name "1_10"
> point 186.31 -124.43 station -name "1_11"
> point 198.19 -127.12 station -name "1_12"
> point 176.97 -115.01 station -name "1_13"
> point 191.00 -109.43 station -name "1_14"
> point 194.21 -92.76 station -name "1_15"
> point 182.67 -112.46 station -name "1_16"
> point 186.84 -71.79 station -name "1_17"
>
> endscrap
> scrap scrap26 -projection plan -scale [0 0 20 0 0 0 1 0 m]
>
> line wall -close on.....
>
> when I ran scrap26 the map is correct:
>
> [image: image.png]
>
> I used this Technic several times and it worked every time.
>
>
> On Mon, Oct 7, 2019 at 12:23 PM Bruce Mutton <bruce at tomo.co.nz> wrote:
>
>> Omri, Alastair
>>
>> I would have thought it almost impossible to draw a whole cave without
>> any point stations in the th2 files, but yesterday a colleague who just
>> self-taught themselves Therion presented me with a 5km long cave that has
>> no point stations defined in the th2 (it has survey stations of course,
>> just not drawn in the scraps).  It is also one of the better looking
>> Therion maps I have come across.  I have yet to pick it apart to see why it
>> works and what the implications are.
>>
>> My suspicion is that it does not properly morph the sketches to the
>> survey network.
>>
>>
>>
>> In response to Omri’s question – if your survey is perfect, and the field
>> sketch as well, then of course an unmorphed drawing will be just fine.  If
>> you have a real survey and sketch, subject to distortions due to loop
>> closures over multiple trips (multiple files), then the loops will not
>> match, and the drawing will need to be morphed due to loop closures and due
>> to scrap joins where the scraps are in different files or different
>> locations in the same file.
>>
>>
>>
>> If, when using Topodroid, as I have seen people over here do, you
>> accumulate all of your survey trips in a single file, and end up with one
>> huge sketch for the cave, in which you manually compensate for any
>> misclosures, then Therion has nothing much left to do.  In that case, it
>> might be fine to do as you describe.  Until someone finds the next big
>> breakthrough passage, then it may or may not be.
>>
>>
>>
>> Bruce
>>
>>
>>
>>
>>
>>
>>
>> *From:* Therion <therion-bounces at speleo.sk> *On Behalf Of *alastair gott
>> *Sent:* Monday, 7 October 2019 19:34
>> *To:* List for Therion users <therion at speleo.sk>
>> *Subject:* Re: [Therion] scrap without stations keeps the original
>> sketch in Topodroid
>>
>>
>>
>> Hi Omri,
>>
>>
>>
>> You cannot have a scrap without any survey points in it. each scrap or
>> th2 file needs 2 or greater survey stations in it to function correctly
>> without warping the image.
>>
>>
>>
>> extended elevations are a bit different (and sometimes need careful
>> adjustment of the legs to fold the extended elevation in the correct way).
>>
>>
>>
>> [Caviat, I know you can have a th2 file with no survey stations in it,
>> but we're not creating rocks today wookware.org/surveys/therion/testrocks
>> ].
>>
>>
>>
>>
>>
>> Regards,
>> Alastair Gott.
>>
>> AlastairGott at hotmail.com,
>> M: 07931779380.
>> ------------------------------
>>
>> *From:* Therion <therion-bounces at speleo.sk> on behalf of עמרי גסטר <
>> omrigas at gmail.com>
>> *Sent:* 06 October 2019 20:31
>> *To:* List for Therion users <therion at speleo.sk>
>> *Subject:* [Therion] scrap without stations keeps the original sketch in
>> Topodroid
>>
>>
>>
>> Hi all,
>>
>> I want to raise a question I've been having with my self...
>>
>> when I'm in the cave I use Topodroid to make the sketch. when I export
>> the map in Therion with "debug on" I see the changes that Therion makes
>> which make the final map different from the sketch I made in Topodroid
>> (sometimes it is a big difference).
>>
>> a few days ago I noticed that if I make a new scrap and move all the map
>> elements that I draw except the stations, the map turns out exactly as I
>> draw it on Topodroid.
>>
>>
>>
>> As I understand it, Therion change the map to overcome or compensate
>> errors or Deviations, especially when there are loops involved, but
>> wouldn't it be more accurate to stick to the original sketch that I drew
>> with Topodroid  in the cave?
>>
>> what do you think?
>>
>>
>>
>> Omri Gaster
>> _______________________________________________
>> Therion mailing list
>> Therion at speleo.sk
>> https://mailman.speleo.sk/listinfo/therion
>>
>
>
> --
> בברכה,
> עמרי גסטר
> 052-6124995
> _______________________________________________
> Therion mailing list
> Therion at speleo.sk
> https://mailman.speleo.sk/listinfo/therion
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.speleo.sk/pipermail/therion/attachments/20191012/cb2430d0/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 42203 bytes
Desc: not available
URL: <http://mailman.speleo.sk/pipermail/therion/attachments/20191012/cb2430d0/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 32562 bytes
Desc: not available
URL: <http://mailman.speleo.sk/pipermail/therion/attachments/20191012/cb2430d0/attachment-0001.png>