Geo Content Management System; comparison of Drupal, Plone, Midgard, Zikula

google maps is a Map server with a low management system (http://ex-ample.blogspot.com/2011/08/geography-gis-google-maps-javascript.html).

http://drupal.org/  alexa (data@august 2011): 390
 It is used as a back-end system for at least 1.5% of all websites worldwide. Because of its plug-in extensibility and modular design (>10000 plugins), Drupal is sometimes described as a content management framework. geospatial modules: http://groups.drupal.org/node/89769
http://www.midgard-project.org/  alexa (data@august 2011): 476 000
http://plone.org/  alexa (data@august 2011): 31 700;
python >57% and Javascript 29% http://www.ohloh.net/p/plone/analyses/latest
http://plone.org/support/sites/sites_listing?industries%3Alist=&countries%3Alist=
http://zikula.org/  alexa (data@august 2011): 70 100
 usermap: http://community.zikula.org/module-GoogleMap.htm

These open source Geo Content Management System are Content Management System where "objects" (users, articles, blogs and images..) can have a Latitude, Longitude position to be displayed on an online interactive map. The online maps link to informational pages/ metadata (wiki pages essentially) on the data represented. They have a map of registered users allowing to build communities geographically, by looking at users location.

The number of locations per content item is not limited to one (as TikiWiki http://info.tiki.org/tiki-index.php; alexa (data@august 2011): 54 000; Tiki contains a number of collaboration features allowing it to operate as a Geo Content Management System).

As a default map source we can select
-OpenStreetMap http://www.openstreetmap.org/,
-Google Maps http://maps.google.com/,
-Yahoo Maps http://maps.yahoo.com/ or
-Bing Maps http://www.bing.com/maps/.

Syndication formats: GeoRSS, KML.

To display the maps, these services sometimes  take advantage of  Openlayers, a JavaScript library for displaying map data in web browsers, with no server-side dependencies: http://www.openlayers.org/