Pleiades Plus

Pleiades Plus is an experimental machine alignment between Pleiades place resources and content in the Geonames Gazetteer. Conceived and prototyped by Leif Isaksen (University of Southampton/Pelagios Project), the current version is produced daily by Ryan Baumann (Duke Collaboratory for Classics Computing). Code and data are available from https://github.com/ryanfb/pleiades-plus. The CSV file produced by the code is also distributed via http://pleiades.stoa.org/downloads/.

Short explanation of algorithm

The algorithm for determining matches iterates through an array of names associated with Pleiades places, checking for exact string matches against names and alternate names in GeoNames. A given name match is included in the output if it meets one of the following criteria:

• if the Pleiades place resource is a point, and the GeoNames resource is within a distance threshold
• if the Pleiades place resource is a bounding box, and the GeoNames resource is inside that bounding box
• if the Pleiades place resource is a bounding box, and the GeoNames resource is not inside that bounding box but is within a distance threshold of its representative point (centroid of associated locations in Pleiades)
• if the Pleiades place resource is unlocated, and the GeoNames resource is contained by the bounding box of the Barrington Atlas capgrid associated with that place (http://atlantides.org/capgrids/)

Columns in the CSV

pleiades_url: HTTP URI (string)

URI for the Pleiades place resource that the code thinks corresponds to the GeoNames resource identified in "geonames_url"

geonames_url: HTTP URI (string)

URL for the Geonames place record that the code thinks corresponds to the Pleiades place resource identified in "pleiades_url"

match_type: string

• "distance": Haversine distance between the Pleiades point or bounding box and the Geonames point was less than 8.0km.
• "bbox": Geonames coordinates are contained by the Pleiades bounding box
• "capgrid": Geonames coordinates within the bounding box of the Barrington Atlas grid square for an unlocated Pleiades place
• "edh": Match manually recorded by the Epigraphic Database Heidelberg

distance: float

Haversine distance in kilometers between the Geonames coordinates and the Pleiades coordinates or bounding box. If match_type="contains" this value will be 0.

pleiades_locationPrecision: string

Values copied from the Pleiades location precision field for this place resource: "precise" or "rough".

pleiades_featureTypes: string of comma-delimited strings

Values copied from the Pelaides feature type field for the place. Values drawn from the Pleiades "Feature (or Place) Categories" vocabulary: http://pleiades.stoa.org/vocabularies/place-types

geonames_featurecode: string

Value copied from the Geonames feature code. Values drawn from the Geonames Features Codes vocabulary: http://www.geonames.org/export/codes.html

Running

./create_pleiades_plus

Outputs to data/pleiades-plus.csv.

Assumes default Ruby (via e.g. rbenv) is JRuby in Ruby 1.9 mode (FasterCSV as require 'csv') and bundler.

If GNU parallel is installed, it will be used for parallel processing.