<s>
Therion	B-Language
is	O
free	B-License
and	I-License
open-source	I-License
cave	O
surveying	O
software	O
designed	O
to	O
process	O
survey	O
data	O
,	O
generate	O
maps	O
and	O
3D	O
models	O
of	O
caves	O
,	O
and	O
archive	O
the	O
data	O
describing	O
the	O
cave	O
and	O
the	O
history	O
of	O
exploration	O
.	O
</s>
<s>
Therion	B-Language
was	O
developed	O
by	O
the	O
Slovak	O
cavers	O
Martin	O
Budaj	O
and	O
Stacho	O
Mudrak	O
but	O
is	O
available	O
in	O
English	O
.	O
</s>
<s>
It	O
runs	O
on	O
a	O
wide	O
variety	O
of	O
platforms	O
including	O
Linux	O
,	O
Windows	O
and	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
.	O
Therion	B-Language
is	O
available	O
as	O
part	O
of	O
standard	O
distribution	O
of	O
Debian	O
and	O
Ubuntu	B-Operating_System
(	O
operating	O
system	O
)	O
Linux	O
distributions	O
.	O
</s>
<s>
It	O
is	O
free	O
software	O
,	O
released	O
under	O
the	O
terms	O
of	O
GNU	B-License
GPL	I-License
,	O
with	O
source	O
code	O
available	O
.	O
</s>
<s>
Survex	B-Language
is	O
used	O
for	O
the	O
centreline	O
error	O
distribution	O
if	O
installed	O
.	O
</s>
<s>
The	O
(	O
UK-based	O
)	O
Cave	O
Surveying	O
Group	O
has	O
been	O
using	O
Therion	B-Language
along	O
with	O
PocketTopo	O
and	O
DistoXs	O
to	O
train	O
cavers	O
and	O
improve	O
the	O
quality	O
of	O
surveying	O
by	O
the	O
use	O
of	O
real	O
time	O
measurement	O
that	O
is	O
available	O
in	O
Paperless	O
surveying	O
.	O
</s>
<s>
Therion	B-Language
is	O
used	O
in	O
several	O
large	O
projects	O
for	O
the	O
documentation	O
of	O
cave	O
systems	O
.	O
</s>
<s>
Not	O
everyone	O
finds	O
the	O
results	O
satisfying	O
:	O
"	O
Beginning	O
in	O
2003	O
,	O
the	O
Mulu	O
Caves	O
Project	O
attempted	O
to	O
use	O
Therion	B-Language
on	O
several	O
cave	O
surveys	O
.	O
</s>
<s>
The	O
unmatched	O
feature	O
of	O
Therion	B-Language
software	O
among	O
other	O
software	O
tools	O
for	O
cave	O
surveying	O
is	O
straightforward	O
creating	O
of	O
3D	O
presentation	O
for	O
WEB	O
pages	O
.	O
</s>
<s>
One	O
may	O
export	O
3D	O
model	O
from	O
Therion	B-Language
to	O
3D	O
format	O
.lox	O
,	O
open	O
it	O
in	O
Therion	B-Language
's	O
3D	O
viewer	O
Loch	O
and	O
export	O
data	O
as	O
VTK	B-Language
.	O
</s>
<s>
ParaView	B-Language
software	O
is	O
able	O
to	O
open	O
such	O
data	O
and	O
export	O
them	O
in	O
WebGL	B-Library
format	O
.	O
</s>
<s>
However	O
,	O
because	O
of	O
the	O
difficulties	O
to	O
build	O
a	O
rigorous	O
synthesis	O
and	O
to	O
update	O
the	O
survey	O
of	O
the	O
complex	O
Jean-Bernard	O
System	O
,	O
they	O
passed	O
to	O
the	O
open	O
source	O
software	O
Therion	B-Language
.	O
</s>
<s>
Two	O
articles	O
in	O
the	O
Annual	O
Report	O
of	O
Cave	O
Administration	O
of	O
the	O
Czech	O
Republic	O
2010	O
describe	O
how	O
Therion	B-Language
was	O
used	O
to	O
document	O
the	O
Javoříčko	O
Caves	O
show	O
cave	O
.	O
</s>
<s>
Described	O
as	O
"	O
State	O
of	O
the	O
Art	O
Cave-Drawing	O
software	O
"	O
,	O
Therion	B-Language
was	O
reviewed	O
in	O
Compass	O
,	O
the	O
Cave	O
Surveying	O
Journal	O
of	O
The	O
British	O
Cave	O
Research	O
Association	O
.	O
</s>
<s>
Since	O
that	O
article	O
,	O
written	O
in	O
2004	O
,	O
Therion	B-Language
has	O
continued	O
to	O
be	O
developed	O
and	O
is	O
now	O
considered	O
to	O
be	O
the	O
most	O
capable	O
cave	O
drawing	O
software	O
available	O
.	O
</s>
