OS and FS in archaeology

[Benjamin Ducke]

OK, I think in terms of philosophy we are all very close to each
other which is not surprising as we work in very similar fields
and face very similar challenges.
So maybe let's start talking a bit more about actual research,
problems and progress.

Luca Bezzi wrote:
> Hi everybody,
> First of all I want to thank Stefano for the mailing list he created, I think it
> is very usefull. Unfortunatly me and my firends (Arc-Team) will not partecipate
> very often during the summer (we are all working in different excavations, so we
> have very few time for internet). I saw the interesting discussion and I want to
> write a few words:
> 
> 1)We are close to release the official ArcheOS 1.1
> (http://www.arc-team.com/archeos/index.html), so if you have some suggestions
> please partecipate to the forum. I have some questions I would like some users
> will answer: is it better to put in ArcheOS less software or the software is
> still not enough? Would you like to have some software for laserscanning
> (actually seems that very few people use it in archaeology), or something like a
> 3D CAD (I am thinking about BRLCAD)?... please help us in developing ArcheOS...

Good news! Is there an OS software for laserscanning? Have you looked at
SAGA GIS? It seems pretty powerful in the beta version 2.
What I was missing in the old version of ArcheOS was some good sample
data for each application to play with.
I was also a bit stupified by the fact that I was greeted with a very
blank desktop void of even a menu bar. I had to find out that you need
to move the mouse cursor to the bottom to popup the starter menu ...

Maybe put some presentations, PDF documents etc. on the Desktop
to get people started?

> 
> 2)Since many years we are working with only FS and OS software in archaeology,
> but I think I still know how some closed software is working. I just want to
> confirm what Benjamin already said. Often OS and FS software is better than
> closed software: there are some work in archaeology that I really don't know how
> to do with closed software. For example if I want to virtually reconstruct the
> archaeological record (that I destroyed when I digged), I need to use the voxel
> graphic, so my best choice is Grass and Paraview
> (http://www.arc-team.com/html_en/OpenSource_en_Presentations.html)... I don't
> know closed software that can do the same (I would like to know if there is
> some). And this is only one example.

I looked at your presentation and was delighted by the progress you are
making with Voxel representations.
Some points I would like to note (re. page 11 of the PDF presentation):

The VTK-model you are creating using r3.out.vtk seems to be a bit of a
"fake"? As Sören explained to me, what it does is take a GRASS voxel map
and squeeze/stretch the individual voxel columns so they fit between the
two boundary surfaces (top and bottom).

Apparently the preceeding r3.mapcalc command just creates a cube of
voxels to be fitted between the surfaces. Why do you store each voxel's
individual 3D position in the output? Given that r3.out.vtk resp.
the VTK engine manipulates every 3D cell in the fitting process
individually, this would invalidate their 3D coordinates in the
paraview display, anyhow (yes/no)?

So why don't you just do something like this:

r3.mapcalc "layer1=1.0"

and then glue together the individual layers in paraview so you can
at least operate on the layer numbers?

In addition: how do you represent irregular borders at the *sides* of
your excavation trenches?

While your approach is cool to use with paraview, it seems to me
that for GRASS-based analysis we need a module that performs a
3D-interpolation in the GRASS voxel space itself.

> 
> 3)If I look at my personal experience I think that in our job we can replace most
> of the closed software we normally use with OS and  FS. Personally I think that
> the only gap we have in FS is about the photogrammethric stereo-reconstruction. I
> mean that actually in my opinion there is nothing in FS that you can compare with
> ERDAS's module Orthobase. We tryd to use Stereo and we can say it is a very good
> software, but it is still too instable and too slow. We hope that e-foto will be
> developed very fast, cause it seems to be the only free software that can work
> like Erdas.

Do you have any experience generating DEMs of layer surfaces using
stereo photogrammetry? I would like to replace the tedious total station
point measurements with some quicker mode of data capturing and
stereo photogrammetry looks like a promising candidate.

> 
> 4)When we started to work with free software we tried to speak about it to many
> archaeologists, but there were some problems:
> - often arcaheologists didn't accept the use of the computer in their work
> (expecially in the field). Actually the situation seems to be changing (in a
> better way)

Well, those people are out of the race already. No need to worry about
them. Let's focus our resources on productive cooperations and simply
ignore those computophobics.

> - when we spoke about free software, they confuse it with freeware, so we started
> to speack about open source. Actually we would like to introduce the difference
> between open source and free software, and develope ArcheOS in the direction of
> free software (we had a discussion about this with R. M. Stallman). But the
> problem is that maybe it is too early to speak about this with archaeologists...
> it can generate confusion again.
> 

Yes, but projects like Linux, OpenOffice and Firefox are paving the way 
very fast. Let's call open source open source. People will get used to
it soon enough.

> 5)One of our main objective (in the OpArc project: 
> http://www.arc-team.com/html_it/OpenSource_it.html) was to share the data.
> Actually we didn't find a solution about this, and we think that to solve this
> problem we will need the help of a lawyer (or an expert)... I mean that if you
> are an archaeologist and you want to share the data of your excavation (even
> before a publication), your main problem will be that only the sovrintendence can
> publish arcaheological data. If you share data before the publication of the
> sovrintendence (I am speaking about Italy), you do something against the law (I
> think there is a "decreto" about this...). I didn' have time to study the
> argument, but I think it should be important to do it...

This is exactly the sort of thing that is blocking progress in
archaeology. It is questionable if a law like this could be upheld
when challenged in a higher court, especially on the EU level.
In Germany, the problem is more complicated, as heritage
management is fragmented on the federal level. Definitely plenty
of work for some good lawyers all over the world. But who can afford
them?

> 
> I hope this mailing list will grew more and more. Best regards,
> Luca. 
> 

Yes, so do I.

Benjamin.


-- 
Benjamin Ducke, M.A.
Archäoinformatik
(Archaeoinformation Science)
Institut für Ur- und Frühgeschichte
(Inst. of Prehistoric and Historic Archaeology)
Christian-Albrechts-Universität zu Kiel
Johanna-Mestorf-Straße 2-6
D 24098 Kiel
Germany

Tel.: ++49 (0)431 880-3378 / -3379
Fax : ++49 (0)431 880-7300
www.uni-kiel.de/ufg