OxCal and other radiocarbon date calibration and analysis services

[benmarwick]

OxCal is a very widely used web service for radiocarbon date calibration and analysis. A package to hook into it from R would be very useful, I can't see any specifications for an API. BCal is a related service, but it also doesn't have an obvious API. This lack of an API for both of these may mean they are dead ends for an R package, but perhaps you can see something I can't?

There's also Bacon and clam which are already integrated into R, but perhaps could be packaged more conveniently.

[sckott]

@benmarwick

• Checked out OxCal. Downloaded the application, and I don't see an easy way to get data out of it, do you? We could ask them.
• Bcal - does it just do analysis? or do they give data?
• For both Bacon and Clam, do you think it's worth asking if they'd want to contribute the code to be in a proper R package that's a more general purpose radiocarbon dating pkg? Seems like both use static set of data?

[benmarwick]

Thanks for taking a look. OxCal looks like a lot of work to include in an R package, the program is three components:

• Input module - web based (runs in a browser).
• Analysis program (OxCalWin/OxCalMac/OxCalLinux) - a command line utility for local or server use
• Output module - web based (runs in a browser)

I'd guess that an R package would be a wrapper around the command line utility, where to start with that is well beyond me!

Bcal is similar, you input data, it analyses it and performs calibrations with a built-in dataset, and give your results and plots. But there's no documentation of what's going on behind the web interface and nothing downloadable that could be wrapped in a package.

Bacon and clam might be the best bet here, since they're already R-based, packaging them would be more straightforward than the other two. The static data is the calibration curve, you input raw radiocarbon measurements and other related variables and the software computes the intersect with the calibration curve and returns calibrated dates. For example the blue region is the static dataset, the red is the user input, and the grey is the computed radiocarbon age in calendar years (this image is classic OxCal output, very ubiquitous in archaeology)

More details on the process: http://c14.arch.ox.ac.uk/embed.php?File=calibration.html

Do you have a standard email that you use to approach people to introduce rOpenSci? I don't know the bacon/clam developers, but I've heard of a few unrelated people attending workshops on them, so it seems to be gaining an audience.

Update: just came across BChron (CRAN, maintainer's page) which seems to be very similar as a radiocarbon calibration tool. The author of that package has a few others that might be suitable for the rOpenSci stable, see what you think!

[sckott]

thanks for all the info @benmarwick

We do essentially have a email template I have sent to various groups about making their data more accessible. Do you think I should email clam and/or bacon folks?

BChron looks interesting. Good catch. I'll have a look