Open Historical Map
Open Historical Map (OHM) (http://www.openhistoricalmap.org) is a site that uses the OSM software stack as a foundation for building an open source, user-editable historical map. This project's goal is to create the world's most universal, detailed, and out-of-date map. OHM will focus on the mapping the geo-objects that OSM is great at mapping - shorelines, political boundaries, buildings, ways, and points of interest. Future and other efforts may engage in discussing historical actions, events, people, and movable items.
Note: As opposed to other projects such as OpenSeaMap, OHM makes use of its own database independent of OSM.
- 1 OHM-Related Resources
- 2 Editing Maps in OHM
- 3 Google Summer of Code proposal
- 4 Using the data
- 5 Short-term plans
- 6 Keys proposed
- 7 Related OSM Projects
- 8 Conversations
- 9 OHM-related mashups
- 10 References
- Production OHM
- Dev / Staging OHM
- Historic@openstreetmap.org mail list
- Slack: #openhistoricalmap on OSM US Slack
- Github: https://github.com/OpenHistoricalMap
- Open Historical Map/Projects
- Open Historical Map Tasking Manager
- Open Historical Map Dev Roadmap
- Wikimaps Warper - the Wikimedia Foundation's map warper enables direct tracing of warped maps into OHM using the ID editor.
Editing Maps in OHM
Because OHM is a separate application from OSM, users must create OHM accounts to edit maps in OHM.
In-browser editing: OHM supports both iD and Potlatch.
JOSM: you must change the API settings in JOSM preferences to set the OHM server API connection parameter (uncheck the default): use https://www.openhistoricalmap.org/api/. Please note, https: and not http.
You may also edit using JOSM by choosing "Edit with Remote Control" in the dropdown menu next to the "Edit"-button on the website. Ensure that Remote Control is enabled under Preferences in JOSM and that JOSM is running. The api will be connected automatically.
How to map
Note on Transferring Data from OpenStreetMap
Transferring data from OSM is strictly discouraged unless you are the author and sole editor of the map data in OSM. There are many reasons for this, but the primary reason is copyright-related. We would like to preserve the right to distribute as much of OHM's data as possible under the CC0 license or to distribute OHM extracts with the CC0 license, which is incompatible with OSM's OdbL license. To be clear, as of June 2019, there is OSM-derived data in OHM at this time and the markings on the OHM website are incorrect. The OHM community is working to address this.
HIGHLY Recommended Tags
Apply a start date and/or end date to the feature. The format is ISO 8601 format YYYY-MM-DD.
This "qualifies" the mapping data as historical and will make it viewable only during that time period.
If you do not know the actual day, you can just add the year, e.g., start_date=1925.
- 1900..1925 (between 1900(-01-01) and 1925(-12-31))
- before 1910-01-20 (before a specific date - possibly when a photo was taken)
Always add the source=*-tag. Ideally, this will include a URL directly to a source map.
- Ribeiro's_World_Map: https://upload.wikimedia.org/wikipedia/commons/7/74/Map_Diego_Ribero_1529.jpg
- 1853 Mitchell Map of Asia: https://upload.wikimedia.org/wikipedia/commons/f/fc/1853_Mitchell_Map_of_Asia_-_Geographicus_-_Asia-mitchell-1850.jpg
Please tag your map information at the object level. It is highly recommended to license your data as CC0.
Regardless of whether your license requires attribution or not, you can put an attribution here. Of note, OHM is attempting to tag attribution at the object level (POIs, ways, relations) rather than at the changeset level. This is fundamentally different from OSM's approach, which recommends putting attribution at the changeset level. It is expected that any particular changeset might involve a set of objects with multiple attributions that should all be: a) exposed to the editor directly, and b) preserved across changesets.
Wikipedia is a great source of historical information and a great source of ideas for what could be mapped in OHM. Be sure to link to a related article wherever possible. And, be sure to use the language prefix when using this tag, e.g.
This will link your OHM data to a particular wikidata Q code. e.g.
Tracing from imagery
JOSM - works with WMS Server, Tile Servers and local images. See JOSM Imagery Guide for more information.
iD Editor - open the layers panel, click "Custom" and paste in a valid Tile URL template.
Google Summer of Code proposal
A number of projects that are in the Wikimaps, OSM, OHM, Wikimedia area would benefit from the temporal flexibility in the OSM tool stack. This would allow us to use data across projects, using layers from multiple sources at different time periods. These projects include:
- Design a how-to map.
- Enhance iD and The Rails Port so that meta-data hooks are added to the code that allow for custom deployments of both software. The intent is to support their use as dedicated user interfaces to certain applications (such as medieval walking path editing) while still using a generic data source.
Using the data
There are a variety of ways to use OpenHistoricalMap Data.
For smallish scale it is possible to download data using JOSM. Two alternatives now exist for larger volumes of data or larger areas:
- A weekly OHM planet file (see http://planet.openhistoricalmap.org/).
- A special Overpass instance at https://overpass-api.openhistoricalmap.org/api/interpreter. You can use it within Overpass Turbo by setting the server to
https://overpass-api.openhistoricalmap.org/api/(Settings -> Server).
See also these pages for the legal attributions:
- OHM/Dev - get The Rails Port, Mapnik, Mod tile, and Nominatim up and running at http://www.openhistoricalmap.org
- OHM/TileServer - Tile serving discussion and docs.
- OHM/Tags - identify OHM tagging conventions
- OHM/Plan - longer-term plans
Related OSM Projects
- Map of Historical objects: historic.place- An atlas of historic sites based on OSM
- HistOSM - An atlas of historic sites based on OSM, out of the University of Heidelberg (HistOSM.org Paper (de) - paper by Michael Auer and Alexander Zipf)
- Historic - OSM Wiki page on Historic sites in general
- OSM-4D (see German version -translation link on top- as English version needs more translation)
- Proposed_features/historic_event - Failed proposal for including events in the OSM database
- Open Historical Map irc: #ohm on irc.oftc.net
- Group on Facebook: https://www.facebook.com/groups/1513784935591521/
- OHM: Vector Tiles & Other Updates Presentation Video, Jeff Meyer, SotM US 2019
- WikiWar: Historical Mapping Adventures, Bert deBruijn video presentation, SotM US 2017
- Tech Changes to the OpenStreetMap Stack, Tim Waters, SotM 2015
- City Stripping: building historical road layouts from todays data, Maps Matter blog post, 11 Dec 2014
- Curating a Historical Map, Living With Dragons blog post, 21 July 2014
- Wikimaps Expeditions, Susanna Anas video presentation, SotM 2014
- Historical maps, Jerry Clough video presentation, SotM 2014
- Open Historical Map reusing obsolete information, David Evans, SotM 2013
- Summary of Hangout December 2012
- OSM & Online Time Machines, Jeff Meyer, SotM 2012
- Mapping History on Open Street Map, Frankie Roberto, SotM 2009