The Pipeline

The geoparser is implemented in modular fashion, as a sequence of steps arranged in a “pipeline”. The aim is to make it easy to switch different components in if desired, for instance if a local POS tagger is preferred to the one supplied here.

As illustrated in Figure Overview of the geoparser pipeline, there are two stages to the geoparsing process:

  1. Geotagging

  2. Georesolution

overview of geoparser pipeline

Overview of the geoparser pipeline

The geotagging step process input text to identify and classify named entities within it, specifically placename entities though other classes can also be found - see The nertag Component.

The georesolution step uses a gazetteer (see Gazetteers) to ground placename entities against specific geographic locations mentioned in the gazetteer. Typically there will be multiple candidates - for example, there are any number of places called “Edinburgh” in the world. The georesolver ranks the candidates in order using various contextual clues.