Aramus Excavations and Field School. Experiences in Using, Developing, Teaching and Sharing Free/Libre and Open Source Software

CAA'2010 Fusion of CulturesFrancisco Contreras & Fco. Javier Melero (Editors)

Aramus Excavations and Field School. Experiences in Using, Developing, Teaching and Sharing Free/Libre and Open

Source Software

A. Bezzi1 , L. Bezzi1 , R. Gietl1 , S. Heinsch2 , W. Kuntner2 , G. Naponiello 1

1 Arc-Team s.n.c./o.h.g., Italy2 Fachbereich Vorderasiatische Archäologie, Institut für Alte Geschichte und Altorientalistik, Universität of Innsbruck, Austria

{alessandro.bezzi, luca.bezzi, ruppi}@arc-team.com{sandra.heinsch, walter.kuntner}@uibk.ac.at

ABSTRACTSince 2006 the archaeological expedition of Aramus (Armenia) is supported only by Free and Open Source Soft-ware. This approach had positive effects on the entire project. In this paper we would like to describe our experience in using, developing, teaching and sharing this kind of applications, focusing the attention both on problems and be-nefits.

Keywords: Free and Open Source Software, Open Hardware, Methodology.

1.Introduction

The project Aramus Excavations and Field School started in 2004 as a cooperation between the University of Yerevan (AM), the University of Innsbruck (AT) and the Institute of Archaeology and Ethnography (National Academy of Science – AM).

The archaeological expedition focused on the invest-igation of the fortress of Aramus, located at 1.450 meters on the plateau of Kothayk, 15 km north-east of Yerevan. The stronghold was founded during the Middle Iron Age (850 – 650 B.C.), after the Urartian conquest of the Ararat plain by king Argišti I (785 – 763 B.C.), and remained occupied till the 3th century B.C. (AVETISYAN 2001, AVETISYAN et al. 2006, KUNT-NER et al. 2010).

In 2006 Arc-Team s.n.c./o.h.g. joined the project, sup-porting the migration from closed source applications to Free and Open Source Software (FLOSS). The experi-ence ended positively and convinced the equipe mem-bers to completely adopt this kind of programs to docu-ment the excavation and, in general, for all the archae-ological analysis (BEZZI et al. 2006a).

Since that time, the mission in Aramus developed fur-ther and many other sub-projects started, with the com-mon purpose to apply the FLOSS philosophy to archae-

ology. This “free orientation” of research and this “open approach” to the discipline produced a cultural back-ground in which different entities (universities, institu-tions and private societies) collaborate to reach a better quality level in every single step of the excavation work-flow, from field documentation to post-processing oper-ations.

In this way, year by year, Aramus became a sort of “open laboratory” where a community of different people (students, professionals, enthusiasts, program-mers, etc...) shares their experiences in using, testing and developing FLOSS in the archaeological field.

In other words free circulation of software, data, knowledge and ideas, leaded to a faster and better re-search development, with positive feedbacks on the whole project.

2.Using and sharing FLOSS

As already noted, in 2006 took place the migration from close to open/free software.

The whole operation needed just few hours and was drastically reduced by changing the old proprietary op-erating system with a new one, ArcheOS 1.2, based on

Proceedings of the 38th Conference on Computer Applications and Quantitative Methods in Archaeology 1Granada, Spain, April 2010

2 Melero, F.J., Cano, P., Revelles, J. / Author Guidelines for CAA’2010 Proceedings

GNU/Linux (BEZZI et al. 2005B, BEZZI et al. 2006b). In this way all the computers of the expedition were equipped with a complete suite of FLOSS specifically packaged to satisfy archaeological needs. In fact Ar-cheOS has been developed to meet the different neces-sities of a normal archaeological research, from data col-lection, storage and management, to data elaboration, analysis and publication. For this reason the long list of software collected in the operating system covers many categories: CAD, Database, GIS, graphic (vector, raster, 3D and voxel), laserscan utilities, photogrammetry, stat-istic, webGIS, etc...

The main advantages of the migration were strictly connected with the four freedoms of the free software definition, written by Richard Stallman and published by the Free Software Foundation in February 1986. In fact, during the expedition, it has been possible to run the programs for any purpose (e.g. forcing raster graphic software to do geographic operations); to study how the programs work (e.g. considering alternative rectification methods in photogrammetric software); to redistribute copies of the programs (e.g. to help students in learning basic documentation techniques in archaeology); to im-prove the programs (e.g. adding new line of source code in software interfaces to connect more hardware devices).

Furthermore ArcheOS brought to the project the sta-bility of a GNU/Linux system and more security against viruses and general malware.

Although the 2006 campaign was committed to ensur-ing the effective efficiency of FLOSS in archaeology, the positive results of the experiment encouraged to pro-ceed with this experience, capitalizing at the same time the fast development of this kind of applications.

3.Developing and improving FLOSS

The collaboration between Innsbruck University and Arc-Team comported mutual benefits.

On the one hand university could support the Aramus mission with professional software, freely distributed, with obvious advantages for students and without addi-tional cost for the budget.

On the other hand Arc-Team could use the field-work experiences in Armenia to further develop ArcheOS, which the society freely releases under the GNU Gener-al Public License. The feedback of Aramus excavation has been very important in building the new versions of the operating system, giving the opportunity to consider the specific needs of an archaeological mission abroad.

One of the main improvement regards the possibility to hardly test the candidate software for every new dis-tribution of ArcheOS. This leads to a better selection of the programs. An example in this sense is the gradual substitution of Scanalyze with MeshLab in the field of laserscan utilities.

Moreover a continuous check on the new software project is granted to eventually insert applications that demonstrate potential in archaeology (e.g. the TOPS utility to interface the system with surveying instru-ments).

When possible, feedbacks and partial implementation of the source code are sent to the developers of some of the programs. Moreover, in special cases, new applica-tions have been written and released under free licenses.

3.1.Writing new applications

Although ArcheOS represents an almost complete ar-chaeological suite of software, in 2007 has been neces-sary to write a new application with the purpose to satis-fy the specific needs of the campaign and optimize some post-processing operations.

In that year, one of the main aim of the project was to map the surface evidences of Aramus hill, trying to re-cognize structural remains, in order to reconstruct the hypothetical plan of the stronghold. In practice, it has been necessary to record with the total station all the vis-ible stones of the hill.

Obviously this kind of work required a long time spent on the field. Consequently a significant amount of hours would have been necessary to manually process the collected data in the laboratory.

To avoid useless wasting of energies, a new applica-tion has been written by Szabolcs Köllö, one of the member of the mission. This software, released under a free license (GPL), sped up the whole process, automat-ically turning the raw data (from total station) into WKT code (Well Known Text), a file format that can be read by most of the GIS contained in ArcheOS. Finally, com-bining this application with OpenJUMP, all the work-flow necessary to convert ASCII text files (raw data) into vector drawing was reduced to automatic computer operations, with a minimum human interaction.

This kind of solution has been possible thanks to the high compatibility that often characterizes different free and open source applications and, especially, to the free-dom to study how the programs work.

4.Teaching FLOSS and sharing know-how

Since 2004 the field work on the Aramus hilltop has been supported by a series of theoretical and practical lessons regarding scientific computing in archeology.

Thanks to the software migration in 2006 this lessons have been improved, due to the opportunity to share with students not only the necessary knowledge, but also the tools to practice it. This step was simplified by the use of ArcheOS, which grants a gradual introduction to the world of open source and free software. In fact, from a didactic point of view, the most important characterist-ic of the system is the possibility to be used “on the fly”, without necessity to be installed in the guest machine.

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Contreras, F., Melero, F.J. (eds.) / CAA'2010 Fusion of Cultures 3

This means that students can practice and test all the software included in the live distribution without com-promising their operating systems. Afterwards, when users feel ready, ArcheOS can be installed on the hard-ware, implementing its performance. According to our experience, this step by step procedure gave good res-ults, avoiding the most traumatic aspect of a software migration. For this reason ArcheOS followed till now a double level in selecting software, that partially can be redundant: beside professional programs, which require a certain know-how, more user-friendly, but less per-forming, applications are usually maintained (e.g. in GIS field GRASS and Udig).

From several lessons of the Aramus Field School is derived the Digital Archaeological Documentation Pro-ject, which collected in a wiki system a series of tutorial in order to share technical know-how regarding FLOSS. This project is meant to be a work in progress, continu-ously updated with new text, media, translations and contributions. All the documents produced are released under appropriate open licenses (generally the Free Documentation License is used), with the purpose to in-volve a larger community.

5.Teaching FLOSS and sharing know-how

Another important aspect of the Aramus project is the choice to share through Internet all the archaeological data and informations collected.

This approach is suggested by the example of the Free and Open Source Software experience, that demon-strated how free circulation of data and ideas normally brings a faster and better development.

In order to achieve this purpose a WebGIS, based on the open source GeoServer and OpenLayer (JavaScript), is actually under development. In the same structure will confluence the finds database, managed by PostgreSQL/PostGIS and the PHP scripting language. An open li-cense (Creative Commons) will be applied to the archae-ological data, with the intention to reach a wide and free diffusion of the informations.

Figure 1: Aramus WebGIS

6.Testing and developing tools and techniques

The choice to use only FLOSS to support the excava-tion had different positive influences on the project. One of the most relevant has been the incentive in research-ing new methodological solutions, encouraged by the accessibility to the source code of the applications.

At the same time, however, technical adjustments were necessaries to correct some inefficiencies in the work-flow. An example of this “trouble-shooting” stage regards the new system, introduced by Arc-Team in 2006, to obtain georeferenced photomosaic (“metodo Aramus”, 6.1). This partial revision of the most common photo-mapping techniques has been required to speed up the field work operations connected with the photo-grammetric modules of the open source GIS GRASS.

Under this point of view, the software migration of 2006 comported both problems and benefits. The prob-lems derived from the alteration of the acquired method-ology (of 2004 and 2005), caused by the radical substi-tution of the instruments (software). The benefits are connected with the new possibility to study and modify the instruments themselves. This situation permitted not only to easily solve the methodological difficulties of the migration (in 2006), but also to find solutions for the always different necessities that the project revealed year by year.

In this sense, under the influence of open source, the research investigated also open hardware possibilities, like in 2008, with the construction of a flying drone for aerial picture and remote sensing (UAVP), that will start operating in Aramus with the archaeological mission 2010 (6.2).

Other problems evidenced by past expeditions are the difficulties to obtain a fast and accurate 3D documenta-tion of the archaeological record and the incompatibil-ity of manual drawing of artefacts with the excavation time-table. Also in this case, during 2008 and 2009, dif-ferent free and open source applications were tested to find new methodologies and solutions. As a result, in 2010, 3D documentation will be produced with Struc-ture from Motion (SfM) and Image Base Modeling (IBM) software (6.3), while scientific illustrations of ar-chaeological finds will be obtained with a semi-automat-ic drawing technique (6.4).

All of this examples show how, according to our ex-perience, Free and Open Source philosophy leaded to a different approach in archaeological discipline, based on highly customizable instruments and techniques, suitable to a wide range of different situations.

6.1.Metodo Aramus

In 2006 the main problem to face the difficulties of an archaeological mission abroad were connected with the basic bi-dimensional photogrammetric documentation of the excavation. Until to that year, Arc-Team's related methodology consisted in carrying on the entire process (rectification, georeferencing and mosaicking) in the



GIS GRASS . Ill fatedly this method was incompatible with the timetable of the mission, due to the time con-suming operations on the field to record all the nine ne-cessary control points for each photo.

To reduce field work to the normal operations of the 2004 and 2005 campaigns (when a standalone close source application was used to georeference and rectify the photos with only 4 control points) a new system was developed. The “metodo Aramus” consists in combining different software to create georeferenced photomosaic. The work-flow starts with the elaboration of the control points coordinates in a text editor (Kate). Then the AS-CII file is imported in GRASS (GIS), where is trans-formed in a raster georeferenced model of the target area. The model is used in e-foto (photogrammetry soft-ware) to rectify every single photo of the entire photom-osaick. Finally the rectified images are mosaicked in GIMP (raster graphic software). The result can be im-ported in every GIS for further operations, like vector drawing of the layers (e.g. in OpenJUMP).

Figure 2: Georeferenced Photomosaic

The entire process can be compared, in therms of time consumption, to the old methodology applied in Aramus till 2005, but the georeferenced photomosaics reached a better quality concerning the equalization of brightness and contrast of the single pictures. Moreover the entire process grants a better human control in every single step, considering also the possibility to directly influ-ence the quality/quantity (resolution/megabyte) relation-ship of the final result.

Until now, after four years, the “metodo Aramus” is still used in the official campaign and further developed thanks also to the community contribute.

6.2.Open Hardware (UAVP)

In 2006 the Aramus excavation was supported by a re-mote-sensing sub-project, which covered the entire area

of the hill with aerial photo-mapping techniques. The operation was possible thanks to the professional sup-port of Klaus Kerkow and Christine Hanisch and in par-ticular to the generous effort of the Ministry of Defence and of the Armenian Air Force, which provided a heli-copter.

Tacking advantage of the new possibilities offered by open hardware projects, future remote-sensing research will be improved by the use of an UAV (Unmanned Aerial Vehicle).

A preliminary study to choose the best solution in building a flying drone, was conducted by Arc-Team in 2008 and leaded to the selection of the UAVP (Univer-sal Aerial Video Platform). This project, developed by Wolfgang Mahringer and released under GPL, met the peculiar necessities of flying stability and manoeuvrabil-ity to face a remote-sensing campaign, oriented to photo-mapping and survey (BEZZI et al. 2008, BEZZI et al. 2009).

The first working prototype was completed in 2008 and partially modified during 2009, in order to improve the functionalities of the remote-sensing device.

Actually the positive response of the flying test indic-ate a realistic use of the drone in Aramus during the 2010 campaign.

Figure 3: UAVP

6.3.SfM and IBM

In 2009 Arc-Team started a series of tests to apply Com-puter Vision techniques to part of the photographic doc-umentation recorded in Aramus during the past years. The objective of this experiment was to virtually recon-struct some stratigraphic contexts that successive ar-chaeological destructive investigations compromised.In practice this technology allows to obtain three-dimen-sional model of reality from a set of photos taken with a normal (not calibrated) digital camera. For this reason it represents probably the best choice in order to recover spatial informations from past excavations.Computer Vision science, in fact, “is concerned with the theory behind artificial systems that extract information from images” (wikipedia, 2010-02-01). More specific-

Proceedings of the 38st Conference on Computer Applications and Quantitative Methods in ArchaeologyGranada, Spain, April 2010

CAA'2010 Fusion of CulturesFrancisco Contreras & Fco. Javier Melero (Editors)

ally the discipline branches known as Structure from Motion (SfM) and Image Based Modeling (IBM) refers to process of 3D structure reconstruction by analysing the motion of an object over time.The positive responses of the tests confirmed the high potentialities of this technique in archaeology and its compatibility with Aramus project peculiarities. In par-ticular this method does not require specific know-how. The whole process is quite simple and can be easily un-dertaken by students in a field school. Human approach to the work-flow is concentrated in the first step, during the data acquisition, and simply consists in taking pic-tures of the object from different view points. On the other side, all the complex operations to extract 3d in-formations form images are delegated to the artificial in-telligence. Moreover Computer Vision is mostly based on software (above all Bundler, PMVS2 and MeshLab, for post-processing) and no expensive or encumbering equipment is required. This make this technology partic-ularly suitable for archaeological mission abroad (only a camera and a computer are required).Basing on our expectations, in 2010 campaign will be possible to register 3D surface of the layers, employing a more accurate kind of documentation than the bi-di-mensional photo-mapping technique. In a second time these data will be processed to reconstruct the entire ar-chaeological record in voxel graphic (BEZZI et al. 2006c).

Figure 4: Reconstruction of stratigraphic context with SfM and IBM techniques

6.4.Semi-automatic drawing technique

Up to now one of the most urgent problem in Aramus expedition regards the documentation and, consequen-tially, the study of the artefacts recovered from the ex-cavation. The main difficulty derives from the great amount of finds, that can not be completely studied dur-ing the mission in Armenia and, at the same time, can not be easily transported in Europe for further investiga-tions.

Although, in normal condition, all the material is prelim-inary recorded with photographic techniques (to avoid arbitrary selections in future analysis) it has been almost impossible to reach a complete documentation of the artefacts with standard scientific pencil illustration, due to the excessive time-consumption of manual drawing.To avoid this problems, trying to completely document the collection of finds, in 2010 will be adopted a new methodology based on the semi-automatic drawing with software. This system, born from a collaboration between Arc-Team and Simone Cavalieri, has been de-veloped in 2008 and 2009, and it is actually used in all the excavations undertaken by the society.The first experiments conducted on Aramus material demonstrated how this technique can significantly speed up the drawing process, reaching at the same time a styl-istic standardization of the single illustrations. This res-ult is achieved thanks to a combination of Free and Open Source Software that, through five steps, allows to obtain black and white non-photorealistic images of every kind of material, compatible with hand-made pen-cil scientific illustrations.

Figure 5: Semi-automatic illustration

The complete work-flow starts from a digital picture of the find, rectified with a photogrammetric application (e-foto), and proceeds with the automatic or manual edge detection of the subject (OpenJUMP or jSVR) and the shading with stippling technique (Stippler). For pot-tery artefacts the illustration is integrated with the sec-tion profile, recorded with mechanical instruments.According to our tests, this system is compatible with an archaeological mission abroad and with the didactic aims of Aramus Field School. In fact, in normal condi-tions, a semi-automatic illustration rarely needs more than thirty minutes (also for complex artefacts), while manual drawing can take over two hours. Moreover no

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particular skills are required with this technique, mostly based on non-interactive software: human support can be reduced to a general control and minor stylistic oper-ations. In this way, acceptable scientific illustration can be done also by non professional drawer, like students or enthusiast.

7.Conclusions

In conclusion it is possibly to summarize our experi-ence with FLOSS in Aramus like a positive experience in sharing tools (software), knowledge (teaching) and data (web publication).

In particular it has to be considered that the software migration in 2006 ended without critical problems. Re-garding performance and stability, most of the free and open source software demonstrated a quality compar-able with closed applications (under some aspects even better than). Didactics was improved by the chance to share the applications with students and public access to the source code helped research development in many branches. Moreover FLOSS philosophy had positive in-fluence in archaeological discipline orienting to a free publication of the data, in the hope to promote transpar-ency and objectivity in the academic research.

Figure 6: The hill of Aramus

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Aramus Excavations and Field School. Experiences in Using, Developing, Teaching and Sharing Free/Libre and Open Source Software

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