OpenStreetMap Americana

From OpenStreetMap Wiki
Jump to navigation Jump to search
For the city in Brazil, see Americana.
Open bug tracker
OpenStreetMap Americana logo.png
OpenStreetMap Americana
Americana collage.png
Authors: Clay Smalley, Brian Sperlongano, et al.
Based on: OpenMapTiles, Planetiler, MapLibre
Slippy map:
Style license: CC0 Public Domain Dedication
Source code: ZeLonewolf/openstreetmap-americana

A quintessentially American map style

OpenStreetMap Americana is a public domain renderer being developed by members of the United States mapping community. The project began in May 2021 with a goal to eventually become part of the OpenStreetMap U.S. website, similar to regional renderers maintained by other OSMF local chapters in Europe and Asia. As of November 2022, it is currently in the early stages of development, with an initial focus on driving technical requirements in the underlying renderer and on the server side and cleanup efforts in the OpenStreetMap database.


Americana applies cartographic practices that are characteristic of maps published in the United States. American publishers have developed a system of conventional symbols and line treatments that is distinct from – and often incompatible with – those used by their continental European counterparts.[1][2] However, most preexisting OpenStreetMap-based renderers have been designed according to European conventions, making OSM itself feel unfamiliar and counterintuitive to some mappers. Americana departs from other OSM renderers in favor of American conventions, demonstrating the versatility of the OSM data that underlies all these renderers.

As a starting point, Americana currently resembles a road atlas, as roads were some of the first features to be implemented. The style does not slavishly copy a particular map or map publisher; instead, it hews to a "typical" road atlas aesthetic. Whenever a new feature is introduced, contributors survey a number of print maps for inspiration. Although the project began with a focus on road features, it is not limited to motorized transportation. As the project begins to focus on higher zoom levels and a broader set of features, other design sources may become relevant, such as city tourist maps and topo maps. See this brainstorming document for more ideas that have been proposed for the project roadmap (no pun intended).


Technically, Americana is not only a map style but also a Web application that displays the map. This application provides interactive map features that are infeasible in a conventional map style:

  • Cities are labeled in both your preferred language and the local language, if the names differ. Set your preferred languages in the lower-right corner or by adjusting your browser preferences.
  • A dynamic map legend gives you a visual overview of the various symbols, lines, and fills in this style, based on what is visible on the map in the current viewport.

As for the map style itself, it takes inspiration from multiple map genres. Features inspired by political maps:

  • Places and points of interest use familiar symbology, such as a star on each state capital (capital=4).
  • At low zoom levels, urbanized areas are highlighted in gold.
  • Boundary lines are emphasized by a colored glow.
  • Disputed boundaries (boundary=disputed) are distinct from mutually acknowledged boundaries.
  • Coastlines (natural=coastline) are outlined except across the mouths of large rivers, and riverbanks and lake shores are also outlined at high zoom levels.

Features inspired by road atlases and road maps:

  • Highways in over 60 countries[3] are marked by route shields instead of a one-size-fits-all symbol ("pancake text"). A wide variety of state, county, and township route shields accurately reflect the distinctions made by road signs while maintaining legibility at a small scale.
  • Along a concurrency, each route shield is placed as a single unit but laid out along the path of the roadway. This is the preferred approach of cartographers and geographers.[4]
  • Expressways (expressway=*) are given extra prominence regardless of road classification.
  • Toll roads (toll=yes) receive a distinct color regardless of road classification.
  • At lower zoom levels, streets are depicted as thin strokes corresponding to their centerlines, in contrast to the road casings found on European maps.[5]
  • Unpaved roads are distinguished by an alternating fill, in contrast to European maps that use an alternating fill to represent railroad tracks.[1]
  • Railroad tracks are distinguished by tick marks resembling railroad ties.[1]

Features inspired by city guides:

Americana's use of MapLibre and OpenMapTiles (through Planetiler) differentiates it from previous open-source renderers used by the U.S. community:

  • Map data is rendered from vector tiles on the client side, resulting in seamless transitions as the user zooms in and out. Labels are automatically localized into your preferred language.
  • Complex features are generalized at low zoom levels, for example by performing Ramer–Douglas–Peucker simplification.
  • Label placement is in general more highly optimized. For example, lake and reservoir labels are laid out along the curve of the main channel. This uptown area has more road label density than the comparatively blank openstreetmap-carto rendering, because roadways that had been frequently split due to turn lane tagging have been merged into longer linear features.

Technical details

Americana is implemented as a MapLibre style that loads OpenMapTiles vector tiles. Unlike most styles, this style is assembled on page load in JavaScript code using a mechanism called runtime styling. Accompanying runtime styling code draws shield images on demand. The style is compatible with any OpenMapTiles-compliant tileset, including those generated by Planetiler.

The legend extracts currently visible features using a mechanism called feature querying. The name of each route network comes from Wikidata's items about highway systems.

How to contribute

If you are interested in contributing to these or other aspects of the renderer, please join the #americana-map-style channel in OSMUS Slack, or start a discussion on GitHub. Bug reports and pull requests are welcome, as are feature requests and insights about user expectations.

See also

Notes and references

Further reading

External links