Geology and Paleontology Office

Since its beginning vertebrate ichnology has based the sharing of data and morphologies on outline drawings and qualitative descriptions of tracks. Though this methods are fundamental for the definition and the understanding of vertebrate tracks, they introduce a high level of subjectivity, due both to the drawing ability and to the sharing methods (eg copies from old journals), which do not allow a precise quantitative approach to ichnology, as, eg, shape analysis.

SUMMARY - Principles of Ichnoarchaeology: new frontiers for studying past times - Since its origins, Archaeology has evolved by interaction with other disciplines, and, in particular, the Earth Sciences have provided major tools for archaeological analysis. Among the branches of Earth Sciences, Ichnology represents a new, promising field for application in Archaeology. The present work explores the application of ichnological methods and themes in Archaeology, as Ichnoarchaeology. Despite case studies on archaeological traces, a uniform, consistent approach has been lacking. As a consequence, archaeologists are still not taking full advantage of traces. This study aims to establish a basis for a coherent, uniform framework by presenting the major themes of Ichnoarchaeology through state-of-the-art case studies. It demonstrates the potential for the study of archaeological traces, and encourages collaboration among scientists of different fields to deepen the knowledge of our cultural heritage.
RIASSUNTO - Principi dell’Icnoarcheologia: nuove frontiere per studiare il passato - Fin dalle sue origini, l’Archeologia si è evoluta interagendo con altre discipline; in particolare le Scienze della Terra hanno fornito importanti strumenti per l’analisi archeologica. Fra i rami delle Scienze della Terra, l’Icnologia rappresenta un nuovo e promettente campo di applicazione in Archeologia. Questo articolo esplora l’Icnoarcheologia, ovverosia l’applicazione di tematiche e metodi icnologici in Archeologia. Sebbene esistano giΰ diversi studi sulle trace archeologiche, finora manca un approccio uniforme all’argomento: di conseguenza gli archeologi non stanno traendo pieno vantaggio dale tracce. Questo studio mira a stabilire una base logica e uniforme all’Icnoarcheologia, presentando le sue tematiche principali attraverso casi di studio da manuale. Vuole inoltre dimostrare le potenzialitΰ dello studio delle tracce archeologiche e incoraggia la collaborazione fra scienziati di campi differenti per approfondire la conoscenza del nostro patrimonio culturale.

During the last decade, several research groups have
started using new methods for the documentation of
footprints (laser‐scanner, photogrammetry) that
brought to the diffusion of three‐dimensional models.
These techniques come alongside the classical methodologies
used since the beginning of vertebrate ichnology
to share data and trace morphologies, i.e., outline
drawings and qualitative descriptions of tracks.
Though these methods are still fundamental for the
definition and the understanding of vertebrate tracks,
they introduce a high level of subjectivity, which do
not allow a precise quantitative approach to ichnology.
Modern approaches introduce an objective way
for collecting data, but, their sharing is still related to
direct contact among authors, thus preventing that
jump towards a quantitative approach that ichnology
needs.
The ICHNOBASE project thus aims to create the first
comprehensive online database on trace fossils, allowing
to organize, store, and retrieve large amounts of
ichnological information. The project bases on a relational
database controlled by a web‐interface for data
input and retrieval. The architecture of ICHNOBASE
consists of three interconnected levels, corresponding
to bibliographic, taxonomic and morphological data,
as well as detailed stratigraphical and sedimentological
data of the site/surface bearing the traces
The intention of the ICHNOBASE project is to become
the reference database for ichnologists, who can use it
to exchange classical and 3D data, geographical information.
It thus enlarges the possibility for each researcher
to access objective data and improve the
shift toward quantitative ichnology.

Scanning ichnological specimens is becoming more and more common, although only few papers have been concerned with recording invertebrate traces, using only laser scanning technologies. We used this as a starting point for a comparison between 3D data acquisition methodologies for traces: laserscanning and photogrammetry. Our comparisons are made on specimens collected from the Carboniferous rocks of the Pramollo area. These specimens were chosen because of their wide range of morphologies, and for the high quality and completeness of preservation, but above all they were chosen for the substrate, which varies from fine black siltstone to brown mica rich sandstone. The specimens were firstly scanned with a Nextengine 3D Scanner HD using the standard Scanstudio HD v.1.3.0 software. The specimens were not “whitened” in order to highlight the sensivity of the tool to the mica refraction. Then the specimens were photographed, always without flash, with a Canon G9 (12.1 Mpixel sensor) in fully automated mode and Macro autofocus and with a Samsung Galaxy SII (I9100) mobile phone (8 Mpixel sensor) also in fully auto mode and Macro focus. As the two cameras have different resolutions and lenses a different number of picture was taken for each sample. Agisoft Photoscan Pro (v.0.8.5, build 1423) was used to generate photogrammetric 3D models from the pictures, aligned with the functions Accuracy “high” and Pair Preselection “Disabled”, and generated as “Arbitrary” Objects type, “High” Target quality, “Sharp” Geometry type, and the maximum (“0”) Face count. The resulting models were then scaled using the “Set Reference Distance” command. Laserscanner and photogrammetric models were and imported to Innovmetric Polyworks IMInspect (v10.0) to be aligned first (using ImAlign) and then compared (using ImInspect). NextEngine models showed that when micas are very abundant a marked roughness of the surface due to the
reflection of the beam by the minerals, ranging from step distance (0.15mm) up to 0.5. These peaks are not present in photogrammetric models, which, on the other hand, present some smoothed surface in proximity of neat steps, as well as a poor detail and high noise in the external part of the model (those with less picture overlapping). The comparison of the models revealed that, also for this field of application, the two methods are equivalent, generating meshes with measurable differences in the order of the resolution of the model (generally 0.15 mm); this is also valid for the models generated with the camera of the mobile phone which, though with a lower resolution and some higher noise than the Canon camera ones, can be considered reliable for ichnological analyses. The higher noise at the boundary and the smoothing effects of the photogrammetric models can be eliminated by taking more pictures of the subject and calibrating the camera (if possible), whereas the roughness given by the laserscanner can be highly reduced “powdering” the sample with talc (or similar) to reduce the reflection.