[mapguide-internals] OpenLayers + SVG = MapGuide Vector Viewer

[Trevor Wekel]

Hi everyone,

I have been thinking about our existing client technology.  Currently, the AJAX and Fusion viewers hit the MapGuide Server for many user interactions (pan, zoom, select, turning layers on/off, etc).  The venerable MapGuide 6.5 ActiveX control was different.  It performed client side rendering and would only request the data from the server as required.  Processing was offloaded from the server and "old" MapGuide was more responsive due to the reduced network traffic.

When MapGuide Open Source was designed back in 2004, browser support for SVG was not on the immediate horizon.  In fact, the first browser to support SVG was Firefox 1.5, released on November 29, 2005.  According to various internet statistics, Firefox had 10% market share at the end of 2005.  Suffice it to say, SVG was not widely available.

Fast forward to today.  Internet Explorer still dominates the market with a 60% share.  Firefox, Chrome, and Safari make up another 35% and they currently support SVG.  So SVG is sitting on the desktop of a third of the internet community.  Internet Explorer 9 will also support SVG.  The IE9 beta is being released as I write this email http://www.microsoft.com/presspass/presskits/internetexplorer/.  As Internet Explorer 9 is adopted, SVG will be deployed to the rest of the internet (and corporate) communities.

Based on this information, I believe the timing is appropriate to implement an OpenLayers/SVG-based MapGuide vector viewer.  Some may ask, "What about Canvas?"  OpenLayers/SVG is still considered better than OpenLayers/Canvas.  A decent write up and analysis is posted on http://trac.openlayers.org/wiki/Future/OpenLayersWithCanvas 

If I get a resounding "OK" from the community, I will start work on an RFC.  Since OpenLayers is the foundation for Fusion and is sometimes used on its own, I think it makes sense to put the rendering support in OpenLayers and any additional control support (properties pane, etc) in Fusion.


Regards,
Trevor