Maps for HTML Community Group

About the Community Group

The Maps for HTML community group is working to standardize methods of defining interactive geographic maps for websites. The community group is hosted by the W3C (World Wide Web Consortium), and is open to anyone who is interested in maps and web standards.

For more information, consult:

• Maps for HTML Community Group homepage on w3.org

  Includes a blog (infrequently updated), along with other information such as links to the group's draft reports, links to the group's mailing list, social media, and forums, and lists of current participants and chairs.

  Most importantly of all, this is where you join the group! Look for the “Get involved” heading and the “Join this group” link. You'll need to create a W3C website account, and accept the W3C Community Contributor License Agreement. If you have an employer with rights to work you create, they may need to join on your behalf.

• “About” page for all W3C-hosted community groups

  With details on the process and legal/intellectual property requirements for community group participation.

• The group mailing list archive

  Contains a history of notices and discussion. However, most discussion happens within the GitHub project repositories.

• Maps4HTML organization on GitHub

  Most work by the group can be found here (including this web page).

• Maps for HTML is on YouTube

  The Maps for HTML Community Group has a channel on YouTube.

Specifications and Reports

The group is currently working on four reports (which are all drafts and subject to change):

• The W3C and OGC held a Web mapping workshop, and we published a report of the results.

• Use Cases and Requirements for Standardizing Web Maps (GitHub repository)

  An overview of why HTML needs a built-in map viewer element, which can combine multiple layers into an interactive view.

• An explainer of the MapML proposal. The explainer is based on a template recommended by the W3C TAG, and may be the best place to start in trying to understand the substance of the MapML proposal.
• MapML specification (GitHub repository)

  Map Markup Language (MapML) is a proposal for a new document format for describing maps, which could contain a mix of tiled images, vector features (e.g., points, lines, polygons), and hyperlinks to related resources.

  Includes a proposal for how the HTML map viewer and layer elements could be defined. MapML documents could be used as layers in an HTML map viewer.

• MapML UCR Fullfillment Matrix (GitHub repository)

  Hosted examples and documents how MapML and existing popular web mapping libraries fulfill the Use Cases and Requirements for Standardizing Web Maps.

• MapML Engineering Reports from the OGC Innovation Program
  • Testbed 13 - early community ideas
  • Testbed 14 - improved vocabulary
  • Testbed 15 - improved vector model
• A blog post, detailing how the MapML proposal relates to the HTML Design Principles.

Software projects

The following projects (hosted by the community group's GitHub account) make it possible to experiment with the proposed specifications:

• Web-map custom element

  A polyfill of the MapML proposal, as a set of HTML custom elements, using Leaflet as the map rendering engine.

• GeoServer MapML Community Module

  A GeoServer module that enables MapML output, supporting images, features and tiles. There is basic documentation available, as well as instructions on how to install the module.

• Validator.nu for MapML

  An experimental / work in progress fork of the validator.nu project which validates MapML documents. The objective is to validate HTML including map markup as well as independent text/mapml documents.

• HTML-MapML Parser

  An experimental / work in progress fork of the validator.nu HTML parser

Working Demos

Websites that use the custom element and MapML server, hosted by Natural Resources Canada.

• Demo MapML viewers

  Interactive map viewers, with maps on various subjects and in various projections, including arctic views (not supported by most web map tiling systems).

• Vector example

  This is an HTML document containing map markup inline, representing vector data according to the MapML <feature> proposal.

Related standards and document formats

The following standards may be of relevance to maps in HTML:

• OGC Standards and Supporting Documents

  The Open Geospatial Consortium (OGC) publishes standards for map-related data, some of which are used or adapted by MapML:

  • Web Map Service
  • Web Map Tile Service
  • Tile Matrix Set
  • Simple Features
• GeoJSON specification

  IETF standard RFC 7946 is a standardized representation of vector feature data in JSON structure.

• Geo URI specification

  IETF RFC RFC 5870 is a URI scheme allowing WGS 84 locations to be conveyed in URLs conforming to a specified URI scheme.

• CSSWG proposal: CSS primitive for per-element panning and zooming

Other links

The following related projects aren't controlled or published by the community group, but may be of interest:

• Spatial Data on the Web Best Practices and Use Cases and Requirements

  These reports were prepared by the Spatial Data on the Web Working Group (now Interest Group), a joint project of the OGC and W3C. Some of the recommendations are relevant to map viewers and map data servers.

• The Responsible Use of Spatial Data

  A report on responsible use of Spatial Data on the web by the Spatial Data on the Web Interest Group.

• OpenLayers

  An open source JavaScript library for building custom Web maps.

• Leaflet

  An open source JavaScript library for building custom Web maps.

• SVGMap

  An alternative to MapML for standardizing interactive web maps, building on the ability of SVG to mix image tiles with vector features and hyperlinks.

  See the related proposals for standardizing key new SVG features: SVG Tiling and Layering Module (proposal) and SVG globalView proposal