[Therion] Spikes and shadow passage in Loch output

[Stelios Zacharias]

I am new to Therion and as far as I know the only one in Greece 
currently trying to use it. This is my first attempt to use it for 
real data from a larger cave. I have many friends here in the Greek 
topo community waiting for me to learn how to use Therion well enough 
to pass on the knowledge. I have many questions which I will be 
asking over the course of time.


At 14:51 16/11/2007, you wrote:
>Quoting Stelios Zacharias <stelios.zacharias at selas.org>:
> > The cave is split into two scraps, although I do not think this is
> > causing the problem. The first difficulty is the appearance of a
> > shadow passage, in the south and west of the diagram. The passage
> > should be in the blue zone for depth, but there is a high echo and a
> > sloping line unconnected to either the high echo or the actual
> > passage. The scrap border is at the meeting point of the three.
>
>This is because there are no survey stations with known Z coordinate in these
>parts of your scraps - therefore therion is not able to determine 
>"altitude" of
>these parts and they are therefore in some average scrap altitude (obviously
>wrong in this case). If you will add station points with 
>corresponding names to
>your scraps, they should be placed in correct altitude.



OK - the passage in question was done by diving, and was never yet 
surveyed. I will have to make up some survey points and include them 
for the loch image over the next few days. If this fixes the problem 
I will re-post.



> > The other problem concerns spikes either upwards or downwards which
> > appear usually in chambers. Two examples of this might be seen at the
> > far eastern end of the survey.
>
>Hmmm, this is a known bug, that happens if single scrap goes over multiple
>altitude levels. Splitting cave into multiple scraps within single altitude
>level usually helps in this case, but it is still a bug that needs 
>to be fixed.


When you write altitude levels, how do you mean - the whole cave only 
has 160m in it, how many scraps should that be split into? There is 
one case of spiking to the south where a passage at -40m is trying to 
reach the surface, the cases at the far east, where some of the 
lowest chambers are growing upwards, a case of a downward spike in 
the northern route a little after the level section in cyan, and a 
few others here and there.


> > If the .th and .th2 files are needed for investigation, I would be
> > happy to send them.
>
>This would help me to find out, where the problem is. Last time I 
>was trying to
>fix this on Wookey's 80km mulu scrap and obviously - this was not possible. So
>some small cave where it appears is welcome.


.th and .th2 files attached. I am not sure about how simple their 
syntax is - it is my first time with multiple scraps, and I know my 
first .th2 has very badly drawn bezier curves, but I am learning still :)


Many thanks for your time.
Stelios
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