OpenLayers: Past, Present and Future

Christopher Schmidt

MetaCarta

What is OpenLayers?

• JavaScript Web Mapping Library
• Creates API for use in JavaScript applications
• Open Source: BSD-ish License
• Started in 2006
• Similar to Google Maps

Project History: Use Case

• MetaCarta creates geospatial search technology
• Search through documents, see results on a map
• Designed for organizations with large document repositories
• Search engine works using map and keyword search as input

Project History: Use Case

• MetaCarta users want to see search results on map
• Want combinations of different mapping data
• Needed to support different data sources, same results
• Designed with overlays in mind

Support for Many Data Sources

• Overlay data on any set of base data
• Allows for easy use of commercial, proprietary or open data
• Supports use of other APIs
• Standardized functionality/look and feel

Project Pre-History

• Started by MetaCarta
• Following Google Maps API
• MetaCarta-only development for 12 months
• API not well-designed, no community
• Several major rewrites -- none very good

Project History

• Final Rewrite in May 2006
• Written with community support early on
• First contributions from community even before first release
• Obvious Success: Quickly adopated
• This is what is known as OpenLayers today

History: Timeline

• First release May 2006
• Refactor, 2.0 in Aug 2006
• Releases every 3-4 months since
• Current version, 2.7, released Sept 2008

Interesting Milestones

• Used by MapBuilder as tile-drawing-library
• Picked up by MapGuide/MapServer 'Fusion'
• Used by Ordnance Survey, IGN France
• Half dozen major supporting organizations
  (OpenGeo, Camptocamp, MetaCarta, DM Solutions, Lisasoft, etc.)

Present

• OSGeo Project
• Dozens of contributors
• Active PSC
• Used by hundreds (thousands?) of websites

Present

• Used by several large mapping agencies
• More than 8000 commits in repository
• Active ticket tracker
• More than 1000 mailing list subscribers

Data Sources

• Raster, Standards Based: WMS, TMS, WorldWind
• Raster, Proprietary: Google, Yahoo, Microsoft, MultiMap
• Raster, Other: MapServer, KaMap, TileCache, Image, MapGuide
• Vector: Markers, SVG/VML/Canvas based Vectors
• Vector Formats: GML, GeoRSS, GPX, OSM, GeoJSON, KML, WKT

Features: Controls

• User interface elements that interact with the map
• Panning, Zooming, etc.
• Drawing tools, vector modification tools
• Measurement
• Scale display
• Easy to build your own controls

Features: Vector Behavior

• Support for loading vector data based on map criteria
• Can load data once, when bounds change, etc.
• Interesting functionality like clustering, paging
• With a protocol, can save to server

Reprojection Support

• For vector data, can change projection of data
• Useful for working with KML, GeoRSS, OSM
• Can also be used when talking to WFS Server
• Often used with Google Maps
• Built in projections, or using proj4js

Future: 2.x

• Continued improvements to vector behavior/protocol support
• Improved documentation, tutorials, etc.
• Continued bug fixes, speed improvements, memory improvements
• 2.8 release in ~2-3 months

Future: 3.0

• Next "major" release -- previous in Aug 2006
• Improvements based on two years of development
• "Backwards compatibility" not required
• Many lessons learned over 2 years!

Future: 3.0 Possibilities

• Change confusing 'LonLat' for projected maps
• Support automatic reprojection of input/output points
• Change vector rendering to accomodate for SVG/VML difficulties
• Drop support for 'deprecated' functionality
• Limit/Remove UI Components as 'core': split into UI libs

Future: GeoExt

• Connector for using OpenLayers with Ext Library
• Take advantage of Ext widgets, and create OL specific widgets
• Being worked on by OpenGeo/Camptocamp
• Discussed at FOSS4G 2008

Gallery

• EveryBlock
• Ride the City
• Houston Crime Maps (GeoDjango)
• OpenStreetMap/OpenCycleMap
• Dutch Directorate for Public Works and Water Management
• California Fire Hazard Severity Zones

Other Interesting Projects

• Camptocamp: MapFish
• DM Solutions: Fusion
• OpenGeo: GeoExt
• MetaCarta: Javascript SDK
• Ordnance Survey: Open Space
• IGN: Geoportail

Next Steps for Project

• Better Documentation/Tutorials
• Improved Beginner Tools
• Target further integration into other tools
• Make switching to OpenLayers easier

International

• Improved international community interactions
• Building/Improving localization
• Improving documentation in foreign language
• Local mailing list/user community? For different langauges

For more...

• Check out http://openlayers.org/
• Join Users Mailing List
• http://openlayers.org/mailman/listinfo/users
• Questions?