Since Semantic Maps uses the Maps API, you can use multiple mapping services. These include Google Maps (with Google Earth support), OpenLayers and Leaflet.
Both Semantic Maps and Maps are based on Semantic Google Maps and Semantic Layers, and are meant to replace these extensions. Having Semantic MediaWiki and Maps installed is a prerequisite for the Semantic Maps extension; the code will not work without it.
Note that the installation instructions might be out of date. Initiation now is done the same way as that of the Maps extension.
Contributing and support
Semantic Maps 3.4.2 is the last release of Semantic Maps as a dedicated extension. It has been merged into the Maps extension, where development continues. All features available in Semantic Maps 3.4.2 are available in Maps 4.0 and later.