Open data
Open data
Some of the places on the map come from OpenStreetMap. This page says which ones, under what licence, and where to get the same rows as a file.
What comes from OpenStreetMap
The viewpoints, trail markers and peaks in the national parks and city forests we cover, and the public chess boards across the Netherlands, are read from OpenStreetMap. Each of those places carries © OpenStreetMap on its own card in the app; the full credit is © OpenStreetMap contributors.
The monuments come from Wikidata, which publishes under CC0, and the clubs and boards people send in through this site are recorded by us. Neither is OpenStreetMap data; the file below holds none of their rows, only a reference where an OpenStreetMap feature was merged into one of them.
The base map is not OpenStreetMap either: it is Apple Maps on iOS and Google Maps on Android.
The licence
OpenStreetMap data is published under the Open Database Licence 1.0 (ODbL). We use it under that licence and offer our copy under the same one. The licence asks three things of us: name the source, offer the derived database as a machine-readable file, and put no technical barrier between the data and the people who want it that the file does not get round. The app needs an account; this page is how the data stays reachable without one.
The file
Every row we take from OpenStreetMap, with the links between them, in one file. It is regenerated after each import and committed with the app, and the production map's OpenStreetMap rows are seeded from this same file.
osm.ndjson.gz osm.manifest.json
- One JSON object per line, gzip-compressed.
- Fields, in order: sourceRef (the OpenStreetMap element as type/id), kind, role, name, cityLabel, lat, lon, attribution, excluded, duplicateOf.
- kind is one of viewpoint, trail-marker, landmark (a peak or an observation tower) or chess-board.
- duplicateOf names the place this row was merged into when two places on the map turned out to be the same thing within 17 metres, as source/reference: osm/node/123 for another OpenStreetMap feature, or wikidata/Q123 when the surviving row is a monument from Wikidata and so not in this file. excluded is true where a place is kept off the map under our exclusion policy. Both are our decisions about OpenStreetMap data, which is why they travel with it.
- The manifest names the source, the licence, the row count and the SHA-256 of the file, so a copy can be matched to the build it came from.
Nothing about players is in it: no accounts, no captures, no faction colours, no ratings.
If something is wrong
A place that should not be on the map, a board that is gone, a name that is off: mail support@chessmeoutside.com. A correction to OpenStreetMap itself belongs on openstreetmap.org, where the next import picks it up.