Traces in World Historical Gazetteer

In Brief

Our conception of traces and trace data was developed in collaboration with Rainer Simon of the Pelagios project, and follows on from work he did in developing the Peripleo pilot web application. In that project, annotations of web records for ancient coins and inscriptions were annotated for ther findspots, or locales. There seems to be broad interest in extending the kinds of records that may be annotated with places, to include events, people, and other kinds of material objects, including works of all kinds.

We in the WHG project have a particular interest in annotating records concerning geographic movement, including individual journeys and expeditions, and flows of all kinds.

We are using the following vocabulary:

  • A trace is any historical entity—something that existed or happened in the past.
  • Trace data is a web resource with a permanent URI that describes a trace in some way. These include datasets, texts, images, etc.
  • Trace annotations for WHG are records linking one or more trace data resource (the "target") with one or more web-accessible records for places (the "body").

Linked Traces format

The Linked Traces format used in WHG so far is a work in progress. It is not so much a format as it is an implementation pattern of the W3C Web Annotation model and vocabulary. We have been collaborating in a small working group to enumerate what patterns may be broadly useful, and in the meantime have created a template for our own use.

The distinctive features of our approach and our annotation pattern include:

  • We are typically annotating a single web-accessible resource describing a trace phenomenon (the target) with identifiers for multiple places relevant to it (the bodies). Our intent is to represent connection between places in this way—for example, via journeys and routes, or being part of an empire or alliance.
  • For each place (body) we want to capture the relation between the trace and the place, and the time period it was related.

What follows is a partial Linked Traces record now indexed in our system. It annotates a dataset, "HernĂ¡n Cortes and the Conquest of the Aztec Empire", with 82 places involved in that event.

    "@context": [
        {"lpo:": ""}], 
    "id": "", 
    "type": "Annotation", 
    "target": {
        "id": "", 
        "type": "event", 
        "title": "Hernan Cortes and the Conquest of the Aztec Empire", 
        "format": "text/html", 
        "language": "en"
    "created": "2020-06-16", 
    "creator": {"id": "","name": "Susan Grunewald","homepage": ""}, 
    "motivation": "linking"
    "body": [
      {	"id": 
        "title": "Azcapotzalco", 
        "place_id": 81731, 
        "relations": [
          { "when": [{"end": "1521-02-22", "start": "1521-02-22"}], 
            "relation": "waypoint"}]
      { "id": "", "title": "Cempoala", "place_id": 82706, "relations": [{"when": [{"end": "1520-05-29", "start": "1520-05-29"}], "relation": "battle_site"}, {"when": [{"end": "1519-06-07", "start": "1519-06-07"}], "relation": "waypoint"}]}, 
      { "id": "", "title": "Cholula", "place_id": 82952, "relations": [{"when": [{"end": "1519-10", "start": "1519-10"}, {"end": "1520-05", "start": "1520-05"}, {"end": "1520-08", "start": "1520-08"}, {"end": "1519-11-01", "start": "1519-11-01"}, {"end": "1519-10-18", "start": "1519-10-18"}], "relation": "waypoint"}]},
      { 79 more ...}
    "tags": [
        "Cortes", "Conquest", "Mexico", "Aztec", "Conquistador", "Tenochtitlan", "Mexico City"]