Use your own OpenStreetMap data

Cartograph never downloads map data by itself: no tile server, no Overpass query, no routing service. You give it an extract of OpenStreetMap, and everything else happens in your browser. That keeps your work private and lets Cartograph run offline once the page is open.

Get an extract of your area

Three easy sources:

1. openstreetmap.org – move the map to your neighbourhood, click Export, then Export again. You get a map.osm file of the visible area (the site limits it to a small area, about one town centre).
2. Geofabrik (download.geofabrik.de) – regions, countries and German states as .osm.pbf. Pick the smallest region that contains your town.
3. BBBike (extract.bbbike.org or download.bbbike.org) – ready-made city extracts, also as .osm.pbf.

Cartograph also reads GeoJSON files whose properties are OpenStreetMap tags, for example from osmium export or overpass-turbo’s export.

Compressed .osm.gz and .osm.bz2 files must be unpacked first; PBF files are read directly.

Open the file

1. In the Poster, Route art or Meet halfway tab, find Map data in the panel.
2. Press Open map file… and choose your file. You can also use File → Open map file (.osm, .pbf, GeoJSON)….

Cartograph reads the file in the background. When it is done, the status bar says how many features it found, and Map data shows the name and the numbers of roads and water features.

Large files: choose the area to keep

A whole region can hold millions of nodes. When the file covers a large area, Cartograph asks you to Choose the area to keep:

• Place lists the cities, towns and villages found in the file.
• Radius around it (km) decides how much to keep – 6 km is plenty for a city poster.

Press Keep this area. The rest of the file is dropped, so the browser stays fast.

Centre the poster

If your old poster centre lies outside the new map, Cartograph moves the poster to the main place of the extract, picks an area that fits and fills the Title with the town name from the file. Adjust Centre, Area half-width and the title as in the first tutorial.

Add a GPX track

On the Poster tab, Add a GPX track… draws a track – your marathon, a holiday walk – on top of the map in the style’s accent colour. GPX, KML and GeoJSON tracks work. Remove the track takes it off again.

Where your data is kept

The map is stored in this browser together with the project, so it opens again from Recent projects…. File → Save project file writes a .cartograph.json that contains the map data too, so you can move it to another computer.

Share link… contains only the settings. Whoever opens the link needs their own copy of the map file; the link says which file it was.

Next: draw GPS art on real streets.