Geotagging - machines-reading-maps/Tutorials-Newsletters GitHub Wiki

All annotations in Recogito, either created manually or automatically, can be associated with an identifier (URI) in a gazetteer or knowledge base. If the gazetteer entry includes geographic coordinates, then the annotation gets also linked to a location.

Thanks to this feature, Recogito enables users to enrich digital maps semantically, creating links to external knowledge bases (such as WikiData, or OpenStreetMap) without writing any code.

The knowledge bases that are currently available in this special instance of Recogito have been selected according to the specific needs of our project's case studies. We have URIs for places in the United Kingdom, the states of California and Minnesota, and the island of Cuba. A historical gazetteer for Central and South America is also available.

Most of the geotagging options in this instance of Recogito come from a list of all WikiData entries that have been categorised as “places” and are located anywhere in our areas of interest. This is an extraordinary resource, created in collaboration with the Living with Machines project. As WikiData features restored, dismissed and disappeared place-entities, this list is especially suitable to annotate historical maps. However, WikiData is not an actual gazetteer, and the coverage may be patchy and inconsistent, with some areas overrepresented and others not represented enough. Another issue we found with WikiData was that, even for large and well known cities such as London, the coverage was not granular enough to produce meaningful annotation. For this reason, we decided to integrate the WikiData knowledge base with urban data from OpenStreetMap (OSM). Due to the large amount of OSM data, we limited ourselves only to few cities that were relevant to our case-studies: Edinburgh, Coventry, Bath, Los Angeles and San Francisco.

We are working towards more, and more complete, solutions, but we thought that this “composite gazetteer” was an interesting and exciting starting point.

Adding a geotag

After selecting the annotation, click on the “add geotag” option. Based on your transcription of the placename, Recogito will try to find a match for it in its internal library, and show its best guess in the annotation pop-up. Once a possible match has been displayed, you have three options:

• The match is correct: you can click on the “confirm” orange button to save the geotag.
• The match is not correct and you would like to change it. This will launch Recogito’s disambiaguation interface, where you can select a place ID that better represents your annotation.
• The match is not correct, and you would like to delete it. Just click on the little bin orange icon near the map.

Disambiguating

If you click on the “change” button in the geotagging window, you will launch the Recogito place disambiguating interface. It will show you other possible matches as both items on a list and pins on a map. You can find the best match by scrolling the list, or browsing the map. Then confirm your choice. You will be automatically redirected to your annotation, which now has a link to the place you have selected. As with any annotation, you can add tags and comments.

If you get too many results and want to reduce the noise, try adding the name of the city in the text field. Some geographic entities have recurring names (for example a cinema called The Odeon) and will appear multiple times, but in different cities.

What if I can’t find the right place?

There are various reasons why the place that you are looking for doesn’t show up among the geotagging options. Wikidata is a contemporary resource, and, although it has entries for many historical features, it is likely that not all features that appear on a 19th century map are recorded with their original name. Also, not everything has an identifier on WikiData. To improve the geotagging process you may try writing a variant name in the disambiguating interface that might be a closer match to the WikiData or OpenStreetMap records.

If you still cannot find a suitable match in Recogito's libraries, you can still create annotations and enrich them with tags and other extra information. You can even use the tags or comment space to add things like external identifiers (like GeoNames, for example) or coordinates.

More info:

At the moment, we are only able to offer geotagging for selected places. You can still annotate maps of other areas, but you will have to either skip the georesolution, or to enter data manually for each annotation.