Bjorn, I can tell you from experience that geoJSON is a very benifical format for dealing with thematic polygon data. It is extremely useful if you want to do custom or dynamic client side processing. I've used it in OpenLayers and in Virtual Earth and Placebase's Pushpin (via GeoJSON to polygon translators that I wrote) for http://www.remapper.com/map/map.aspx REmapper.com . However, one thing you should be concerned with is the level of detail returned from te server. For example mapping the world or hemisphere's worth of data at 3 decimal places will absolutely kill your performance and not add anything that the user could even distinguish. A static geoJSON file that is downloaded to and cached on the client and parsed asynchronisaly on page load would be a good option that would allow you to let the user change thematic display classifications or use proportional to view area classifications without requiring downloading anything from a server or using cumbersome SLD. Good Luck! Matt Priour http://priour.wordpress.com - blog http://www.kestrelcomputer.com - website Kestrel Computer Consulting
Bjorn Sandvik wrote: > > Hi, > > I'm looking at possibilities of using OpenLayers for thematic mapping > (thematicmapping.org), and I think GeoJSON might be a suitable format > for choropleth maps. > > I'm able to generate GeoJSON on the server using PHP, and my country > polygons are rendered in OpenLayers when I'm pasting the GeoJSON code > on: http://www.openlayers.org/dev/examples/vector-formats.html > > My question: What is the best way to load and render a GeoJSON layer in > OpenLayers? > > Thanks, > Bjorn > > http://blog.thematicmapping.org > > > > _______________________________________________ > Users mailing list > [email protected] > http://openlayers.org/mailman/listinfo/users > > -- View this message in context: http://www.nabble.com/Adding-a-GeoJSON-Layer-tp16384418p16392253.html Sent from the OpenLayers Users mailing list archive at Nabble.com. _______________________________________________ Users mailing list [email protected] http://openlayers.org/mailman/listinfo/users
