Context-based Toponym Disambiguation regarding Historical Gazetteer

[This blog post is based on the Master thesis Information Sciences of Bram Schmidt, which he conducted at the KNAW Humanities cluster and IISG. It reuses text from his thesis]

Place names (toponyms) are very ambiguous and may change over time. This makes it hard to link mentions of places to their corresponding modern entity and coordinates, especially in a historical context. We focus on historical Toponym Disambiguation approach of entity linking based on identified context toponyms.

The thesis specifically looks at the American Gazetteer. These texts contain fundamental information about major places in its vicinity. By identifying and exploiting these tags, we aim to estimate the most likely position for the historical entry and accordingly link it
to its corresponding contemporary counterpart.

Example of a toponym in the Gazetteer

Therefore, in this case study, Bram Schmidt examined the toponym recognition performance of state-of-the-art Named Entity Recognition (NER) tools spaCy and Stanza concerning historical texts and we tested two new heuristics to facilitate efficient entity linking to the geographical database of GeoNames.

Experiments with different geo-distance heuristics show that indeed this can be used to disambiguate place names.

We tested our method against a subset of manually annotated records of the gazetteer.
Results show that both NER tools do function insufficiently in their task
to automatically identify relevant toponyms out of the free text of a historical lemma. However, exploiting correctly identified context toponyms by calculating the minimal distance among them proves to be successful and combining the approaches into one algorithm shows improved recall score.

Bram’s thesis was co-supervised by Marieke van Erp and Romke Stapel. His thesis can be found here [pdf]

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Source: Victor de Boer

Posted in Staff Blogs, Victor de Boer

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