Google Maps field type for Custom Metaboxes and Fields for WordPress.
The pw_map field stores the latitude/longitude values which you can then use to display a map in your theme.
pw_map - Save a location on a map. Example:
array(
'name' => 'Location',
'desc' => 'Drag the marker to set the exact location',
'id' => $prefix . 'location',
'type' => 'pw_map',
'sanitization_cb' => 'pw_map_sanitise',
),