Im using the modules stuck very similar to one described here ( Need a simple Google Maps solution; lost in the labyrinth of modules).
Geofield, Openlayers, Drupal 7
The difference is that I dont use Address field for auto detecting the lat/lang from address. The Geofield field widget type is set to "Openlayers map" so the points can be manually added by user to the map when the node is being edited.
Is there any way to limit the maximum number of points that user can mark on map? (to 1)