Gli atti del workshop Archeofoss 2022 sono stati pubblicati in open access su Archeologia e Calcolatori. Li trovate qui http://www.archcalc.cnr.it/journal/idyear.php?IDyear=2023-07-26 come numero 34.1 della rivista.
Ho curato insieme a Julian Bogdani l’edizione di questo volume ed è quindi motivo di soddisfazione, anche per i tempi rapidi con cui siamo arrivati alla pubblicazione grazie al lavoro collettivo degli autori e autrici, di chi ha fatto il referaggio, della redazione e della casa editrice.
Rimane una mancanza in questo volume rispetto alla ricchezza dei due giorni di incontro, delle sette sessioni tematiche, delle discussioni guidate da chi ha moderato le sessioni, ibride eppure vivacissime. La mancanza in parte è fisiologica ma in parte deriva da un certo numero di autrici e autori che non hanno presentato il proprio contributo per la pubblicazione. Ad esempio, nella sessione sui dati stratigrafici che ho moderato con Emanuel Demetrescu erano stati presentati 7 interventi ma solo 2 sono confluiti come paper nel volume.
Nei prossimi anni dovremo fare di più per fare in modo che gli atti raccolgano ancora più fedelmente il convegno.
I am working on the Harris Matrix Data Package specification with the aim of decoupling it from my own “hmdp” tool. An important step towards the adoption of a data format is to have more software implementations. With this in mind, I present a procedure to import, analyze and plot a Harris Matrix data package in R, with the experimental stratigraphr library maintained by Joe Roe.
stratigraphr is a tidy framework for working with archaeological stratigraphy and chronology in R. It includes tools for reading, analysing, and visualising stratigraphies (Harris matrices) and sequences as directed graphs
We load a Harris Matrix Data Package describing figure 12 from E.C. Harris’s manual Principles of archaeological stratigraphy, as modified by T.S. Dye. Please note that we are loading a package straight from a URL, and this could be an institutional repository like Zenodo or OSF.
Warning! The names_from = url parameter is a bit of a hack, and only works because the values in that column are all NULL.
The first approach is to use the same code from the stratigraphr documentation, but it returns an error. Directly loading the data in stratigraphr only works if all contexts exist in the context column of the observations table (the following code chunk is not going to work, shown here for demonstration):
It seems like the context column doesn’t actually contain all contexts, which makes sense because there is no duplication of relationships in the Harris Matrix Data Package format ‒ it’s a tidy format! We can easily work around this by loading the full contexts table.
A Harris Matrix visualization of archaeological stratigraphy, data from figure 12 from E.C. Harris’s manual Principles of archaeological stratigraphy, as modified by T.S. Dye.
It works perfectly!
We still need to include once-whole contexts in the picture, from the inferences table, but apparently this is not yet supported by stratigraphr either.
Summary: the quick way to analyze and plot archaeological stratigraphy data in R
In short, the equivalent to the stratigraphr vignette with Harris Matrix Data Package is:
A Harris Matrix visualization of archaeological stratigraphy, data from figure 12 from E.C. Harris’s manual Principles of archaeological stratigraphy, as modified by T.S. Dye.
It’s slightly more verbose than the original stratigraphr, and it could certainly be improved, but it’s a good way to get started with archaeological stratigraphy data in R.
A few weeks ago I presented a new version of the hmdp tool at the ARCHEOFOSS conference in Rome. You can find the archived presentation on Zenodo.
Harris Matrix Data Package is a proposal for a standardised digital format of archaeological stratigraphy datasets in CSV format, following the table schema developed by Thomas S. Dye for the hm Lisp package, augmented with a metadata descriptor (datapackage.json) that enables consistency checks and streamlined data access with the Frictionless Data tools and programming libraries. In the standard, each dataset consists of various CSV tables and a metadata descriptor, forming a data package. I proposed this standard in 2019 at a previous ARCHEOFOSS conference based on a 2015 work by Dye and Buck [zotpressInText item=”{12096:TZPPQB42},{12096:G2QPMZQT}”].
Based on this proposal, hmdp is a command line program for working with archaeological stratigraphy data in the Harris Matrix Data Package format.
The hmdp init command works both interactively and with explicit command line parameters, and it is centered around the idea that in the Harris Matrix Data Package:
each Harris Matrix is a data package
there is 1 data descriptor
there are from 2 to 7 CSV tables
each CSV table is a resource
The two resources that MUST be present are:
contexts
observations
Most often, excavation data will make use of three other resources:
inferences
periods
phases
Only in case there are radiocarbon dates or other absolute chronology available the two resources should be used:
events
event-order
With the above outline, default presets are defined, and choosing a preset will create the corresponding CSV files (resources). The CSV files are created only with the standard column headers, data must be filled by the user.
The current released version of hmdp init can create a Harris Matrix Data Package from scratch, e.g. in a new empty directory. Support for recognizing existing CSV files and adding the metadata descriptor is in progress.