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Introducing GT-Viz: Visualize FactGrid Data on a Map

GT-Viz is a browser-based tool for visualizing geospatial and temporal data from SPARQL endpoints. You write a SPARQL query, provide the SPARQL endpoint for example FactGrid or Wikidata, and the results appear on an interactive map with a timeline.

It was built by a group of students at RWTH Aachen University as part of the Knowledge Graph Lab course.

Try it here: https://gtviz-kgl.wikidata.dbis.rwth-aachen.de/tutorial

Input

The only input needed is a SPARQL query. A set of built-in example queries covers FactGrid (Thirty Years’ War battles), Wikidata (Napoleon, WW1 & WW2, Magellan and Columbus voyages, Olympic venues), and can be loaded for testing the functionalities. The sidebar holds a SPARQL editor with syntax highlighting and validation. A Help panel documents the expected query variables.

The tool reads these variables from your query results: ?location (WKT point), ?time (date), ?category, ?parentCategory, and optionally ?name, ?description, and ?pathId.

Map View

Query results appear as markers on an OpenStreetMap base layer. Parent categories each get a distinct color; sub-categories within a parent are separated by fill patterns. Clicking a marker shows its name, description, category, and date.

Two display options can be toggled: whether to draw connecting lines between points that share a ?pathId, and whether to show points that have no date.

The Group Visibility panel shows the full category hierarchy from the query results. Individual sub-groups or entire parent categories can be toggled on or off. Item counts are shown at every level.

Timeline and Animation

The timeline at the bottom filters the map to a selected date window. Drag the handles to set start and end dates; the map updates immediately. The Play button animates the window forward through time at an adjustable speed (configurable in days, weeks, months, or years per second).

Historic Map Overlays

As an experimantal feature it is possible to load historic maps. The historic maps are overlayed on the base layer as they only cover a small portion of the globe. For testing we provided a small set of over 20 different historic maps. Only thing needed to integrate such a historic map is a tile server serving the map thus the set of supported historic maps can easaly be extended.

Example: Thirty Years’ War battles from FactGrid

    1. Open https://gtviz-kgl.wikidata.dbis.rwth-aachen.de
    2. Click the lightbulb icon and select “FactGrid: Battles of the Thirty Years’ War” — the endpoint and query fill in automatically.
    3. Click Run. Battles appear across central Europe; the timeline sets itself to 1618–1648.

From there, use the Play button to step through the war year by year, the filter panel to isolate specific belligerents, and the Map Config tab to add a period map beneath the markers.

Feedback

GT-Viz is a student project in its early stages. We are looking for feedback from the FactGrid community on what works, what is missing, and what would be most useful.

→ Take the survey

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