[OpenLayers-Users] Adding a GeoJSON Layer

[mpriour]

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
> Users at openlayers.org
> 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.