Overview

A toolkit for temporal reasoning. aion allows to describe and analyze finite time intervals. It provides methods for:

• Aoristic analysis (Ratcliffe 2000): aoristic()
• Allen’s interval algebra (Allen 1983): allen_*()
• Archaeological sequence diagrams (Dye and Buck 2015).

Installation

You can install the released version of aion from CRAN with:

install.packages("aion")

And the development version from GitHub with:

# install.packages("remotes")
remotes::install_github("tesselle/aion")

Usage

## Load package
library(aion)
## Principles of Archaeological Stratigraphy, fig. 12
## Build an adjacency list
harris <- data.frame(
younger = c(1, 1, 1, 2, 3, 4, 5, 6, 6, 6, 7, 8, 1, 1),
older = c(2, 3, 4, 5, 5, 5, 6, 7, 8, 9, 9, 9, 7, 8)
)

## Coerce to adjacency matrix
## (perform transitive reduction)
strati <- as_stratigraphy(harris, reduce = TRUE)

## Define interface layers
set_interface(strati) <- c("1" = FALSE, "2" = TRUE,  "3" = FALSE,
"4" = FALSE, "5" = FALSE, "6" = TRUE,
"7" = FALSE, "8" = FALSE, "9" = FALSE)

## Stratigraphic graph
graph <- as_graph(strati)
plot(graph)

Contributing

Please note that the aion project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

References

Allen, James F. 1983. “Maintaining Knowledge about Temporal Intervals.” Communications of the ACM 26 (11): 832–43. https://doi.org/10.1145/182.358434.
Dye, Thomas S., and Caitlin E. Buck. 2015. “Archaeological Sequence Diagrams and Bayesian Chronological Models.” Journal of Archaeological Science 63 (November): 84–93. https://doi.org/10.1016/j.jas.2015.08.008.
Ratcliffe, Jerry H. 2000. “Aoristic Analysis: The Spatial Interpretation of Unspecific Temporal Events.” International Journal of Geographical Information Science 14 (7): 669–79. https://doi.org/10.1080/136588100424963.