FOSS4G 2006 Webmap BOF

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The Web Map Client Bird of a Feather (BOF) session (also referred to as the ka-Map/OpenLayers merger BOF or AJAX Map Client BOF) at FOSS4G 2006 met from 1800 - 2000 on Wed 13 Sep 2006, with the intention of identifying common components that could be abstracted and shared between the various Free and Open web map client libraries.


Christopher Schmidt posted a summary of the meeting to the OSGeo webmap-discuss mailing list. (To actively join discussion and reply to the confirmation mail in order to subscribe.)


The following projects (at a minimum) were represented at the BOF:


The meeting participants agreed that the simplest and most effective place to start integrating code between projects would be to select a map tile display engine and abstract it into a library. The map and layer rendering core from OpenLayers was selected for this task, due to its relative simplicity and modularity. By the end of October, the OpenLayers team will spec out an API (tentatively to be called webmap.js) and begin to split out the minimal necessary portions of the OpenLayers code base into this separate library. By that time, each of the participating projects (hopefully ka-Map, OpenLayers, MapBuilder, and Mapbender, at a minimum) will evaluate their needs for a core tile display API and offer recommendations on how best to design the webmap.js library to offer maximum utility to everyone.

Our hope is that, in the future, the new core display library will ultimately be integrated into each project, and be developed collaboratively between the participating projects thereafter.


The following were the notes collected on the overhead screen during the meeting.

Possible Web Map Subsystems?

  • Map display
  • Layer
  • Features
  • Controls (UI widgets)
    • Pan / zoom buttons
    • Zoom bar
    • Modal tools
    • Link to this view
    • Scale ratio
    • Scale bar
    • Ruler
    • Measure area
    • Legend generation
    • Mouse actions
    • Keyboard shortcuts
  • Overlays
  • Popups / info windows
  • Client-side vector drawing
    • Zorn
    • SVG
    • VML
    • Canvas
    • digitization
  • Printing (generating PDF on the server?)
  • Server-side tile generation
  • Coordinate projections
  • Event handling (higher level map semantics? and/or lower level browser semantics?)
  • Documentation!!!!! (lack thereof not a business strategy)
  • Unit tests
  • Framework issues??? or none at all
  • XML processing
  • Licensing? BSD/LGPL preferred for reusability