 <p>OpenLayers <a href="http://www.openlayers.org/" rel="nofollow">http://www.openlayers.org/</a> is the most featureful web-mapping client. It will happily read your data locally via standard GeoJSON files for vectors and geo-referenced images for rasters.</p> <p>You could even grab a bunch of tiles from something like an OpenStreetMap tile server and serve those locally for a pretty background.</p>