Automatic Soil Texture Triangle

As the regular ATOR readers know, since some years we are trying to improve our laboratory's technologies in order to achieve a better metric classification of archaeological data and to expand our research interests in other archaeological sub-disciplines and mainly in archaeo-anthropology (as well as taphonomy and mummiology), archaeo-zoology, archaeo-bothany in general (and carpology and dendrochronology in particular), geoarchaeology and archaeometry. 

Soon we will start a series of post about our lab (aka ATLAB, Arc-Team LABoratory), which is evolving fast thanks to the effort of +Gianluca Fondriest  and +Mattia Segata.

Today I want to illustrate one of the tool we developed to speed up the geo-archaeological interpretation of the soil texture of the different layers during our excavations. This project (which is now in its early stage) starts from the need to use the Soil Texture Triangle to help archaeologists (especially the new diggers) in correctly interpreting the texture components using an objective method like the sedimentation test (because often new archaeologists are not comfortable with more subjective analysis like the Ribbon test or the squeeze-ball test). I leave the explanations of the operations to perform on the field for another post, while I want here to show the small software "geTexture", which +Giuseppe Naponiello developed to use automatically the Soil Texture Triangle from internet.
To illustrate how the application works, I recorded a short videotutorial:

The software is currently just in Italian, but we will translate it in English soon. The development is still active and this can be considered just a pre-release (it will be implemented also with a tutorial explaining how to perform the sedimentation test on the excavation). If you want to help us, on GitHub you can find the source code, while if you need already to use the software, here is the link where is is accessible. In the next days I will try to program also a small app for Android devices.

Stay tuned and have a nice day!

Notes

Some of the results of ATLAB can be seen in the article "Lo Scavo archeologico professionale, innovazioni e best practice mediante metodologie aperte e Open Research" (here in ResearchGate and here in Academia)

The archaeometric excavation

Last year, on November 28, Arc-Team joined the conference "Lo scavo archeometrcio: scienza e tecnologia applicate allo scavo archeologico" (en: "The archaeometrcic excavation: science and technology applied to the archaeological excavation"), which was held in Rovereto (Italy) at the Museo Civico.

During the meeting we gave a presentation titled "Professional archaeology. Innovations and best practice with free technology. Toward an Open Research." Today I uploaded on our server the slides, so that we can share this work (like always under Creative Commons Attribution - CC BY).

As usual the presentation has been done with impress.js through the Graphical User Interface Strut (both GPL licensed) and it is optimized for Firefox or Iceweasel (better visualized here).

Here is a little explanation regarding the single slides:

SLIDE 1

A fast presentation regarding Arc-Team.

SLIDE 2

An animation representing the importance of geocoding in archaeology (from space to site).

SLIDE 3

Differential GPS and Total Station: the main tools needed by archaeologists on the field (to georeference every single element of the archaeological record).

SLIDE 4

Some examples of geocoding in archaeology: everyday work, project in extreme conditions and missions abroad...

SLIDE 5

... survay and excavations

SLIDE 6

In survay projects the geocoding tolerance for archaeology is higher, so that we are testing alternative solutions to build a low-cost and open source GPS with centimetric accuracy, using the software RTKLIB (or its port in Android)

SLIDE 7

All the recorded data (in 2D and 3D) can be imported into an open source GIS.

SLIDE 8

For aerial archaeology it since 2008 we are working with open source DIY UAV, like the UAVP or the KKcopter (in the slide).

SLIDE 9

Our last UAV prototype and an example of 3D pointcloud form aerial pictures.

SLIDE 10

Since 2014 we are testing DIY camera (using the filter of Public Lab) for NDVI and NGB pictures in archaeological remote sensing.

SLIDE 11

Just removing the IR filter, a normal camera can be used for endoscopic prospections in low light conditions.

SLIDE 12

In the field of geophysical prospections we use a DIY  machine for Electrical Resistivity Imaging. The data can be visualized in a GIS (e.g. GRASS GIS in the slide), using the east and north and the resistivity values.

SLIDE 13

Some geoarchaeological analyses can be performed directly on the field, like the settlement test (using the soil triangle) for the texture or the lithologic recognition for the skeleton.

SLIDE 14

Also some basic analytical chemistry can help during the excavation (giving indications on the ancient use of the soil), to verify the presence/absence of phosphates or of organic remains.

SLIDE 15

Other preliminary laboratory (flotation and sieving) analyses can prepare the samples for further investigation. Also in this case we use a DIY machine.

SLIDE 16

Colorimetry can be performed in many ways. Currently we are testing different options, like the open source spectrometer of Public Lab.

SLIDE 17

For some laboratory geoarchaeological analysis (e.g. microscopic morphology) we use normal optic microscopes, while for more advanced studies we externalize the service (e.g. SEM or energy dispersive x-ray spectroscopy)

SLIDE 18

Currently we are testing the potentialities of the FLOSS MorphoJ to speed up the process in carpological remains recognition

SLIDE 19

To document archaeozoological remains in the field, we use the standard digital documentation techniques (in 2 and 3D), with FLOSS (e.g. bidimensional photomapping with the Aramus method or 3D recording through SfM and MVSR)

SLIDE 20

In the evolutionary anthropology field we developed a new technique (anatomical deformation) thanks to the FLOSS Blender

SLIDE 21

The same software (Blender) is used in the process of archaeological forensic facial reconstruction

SLIDE 22

Open source GIS (e.g. GRASS) are the main software we use to process and manage the recorded data

SLIDE 23

Thanks to open source UAV and Blender we experimented new ways to disclose archaeological data in a four-dimensional way (x,y,z,t)

A more detailed explanation of the entire presentation will come soon with the related article. For the topics which were already discussed in AOTR, I suggest to read the related post (see the above bibliography). For the latest experiment (e.g. near infrared, NDVI and NGB; Electrical Resistivity Imaging; Sedimentation test; litologic recognition on the field; flotation and sieving; colorimetry; microscopic morphology; MorphoJ;), we will try to write something as soon as possible.

Bibliography

Lo scavo archeologico professionale, innovazioni e best practice mediante metodologie aperte e Open research (here on Research Gate and here in Academia)

Webography (from ATOR):

3D and 4D GIS

gvSIG

SfM and MVSR

PPT-GUI (tutorial); from pictures to mesh (PPT, MeshLab, Blender); PPT with Bundler MultiTread; PPT with turntable (not recomended); PPT VS MicMac; PPT VS openMVG; recovering old data; underground documentation; big data; low-light conditions; underwater archaeology; aerial 3D; 3D GIS; anthropology;

Aerial 3D documentation

Caldonazzo Castle (case of study);

Archaeological endoscopy

normal endoscopy; IR endoscopy;

Geoarchaeology

genetic color, framework and edge analyses of skeleton; analytical chemistry on the field;

Archaeobothany

Vegetal macro remains indentification;

Evolutionary anthropology
Anatomical Deformation Technique (ADT): validation; ADT Paranthropus boisei; ADT Homo rodhesiensis;

Archaeoanthropology
Archaeological Forensic Facial Reconstruction (AFFR); Digital AFFR: technique validation; AFFR: state of the arts; AFFR: poster;

Archaeological dissemination
Caldonazzo Castle 4D (case of study);

Application of analytical chemistry in the early stages of an archaeological excavations

Analytical chemistry is the branch of chemistry that deals with the qualitative and quantitative identification of specific components called "analytes". It can be useful, in geoarcheology, to investigate the composition of the geological matrix of a given sample.

This science makes use of recognition techniques based on the reactivity and analyzes the tendency of a particular chemical species to react in the presence of specific reagents; in other words, under a practical aspect, it is possible to induce a reaction and to exploit its sensitive aspects to identify the presence or the absence of the analyte we are looking for.

During an archaeological excavation, it can be useful to know if, in the sediment we are removing, are present some components which can be considered as markers of specific past human activities. This kind of archaeological markers are organic substance, carbonates and phosphates and they may indicate the presence of paleosurfaces, middens, agricultural activities (like fertilization) or craftsmanship sites.

The organic substance is composed by chains of carbon, with oxidation state lower than +4, and hydrogen, that bind a number of heteroatoms (mainly oxygen, nitrogen, sulfur and phosphorus); the diagnosis involves the use of hydrogen peroxide [H₂O₂], as a liquid solution, which is poured directly on the soil sample; if some organic substances are present, they generate bubbles with effervescence; the more elevated is the organic concentration, the greater is the effervescence and vice versa.

The carbonates are chemical compounds which contain molecules made of a carbon and three oxygens [CO₃^2-] that bind other elements; the diagnosis involves the use of hydrochloric acid [HCl] in a liquid solution, poured directly on the sample. Also in this case, if the test is positive, it generates effervescence with bubbles (with a direct proportion with the carbonates presence).

This process is illustrated in the following video (H₂O₂ and HCl test from an old Arc-Team's excavation).

The phosphates are chemical compounds which contain molecules made ​​of a phosphorus and four oxygens [PO₄^3-] that bind other elements; the diagnosis involves the use of a reagent, in form of powder, consisting of ammonium molybdate [(NH₄)₆Mo₇O₂₄.4H₂O], antimony potassium tartrate [C₈H₄K₂O₁₂Sb₂.3H₂O] and ascorbic acid [C₆H₈O₆]; such a reagent is mixed with the solution of distilled water in which has been previously dissolved the soil sample: if some phosphates are present, the aqueous solution turns from azure to blue, depending on the concentration of this chemical element.
The process is illustrated in the following videos (phosphates test from an old Arc-Team's excavation):

1. Preparation of the soil sample

 2. Preparation of the analysis

 3. Reading the results

PS
For Italian readers, sorry for the jargon in the videos... everything is recorded from reality