Save/Load a map(OccupancyGrid) centering on cpecific GPS coords

edit

Hi! Maybe the ansver is obvious, but unfo can't understand, how do I make this.

I have UTM->map->odom frames using EKF and navsat_node, so all local and GPS coordinates are known (i don't use laser scans and SLAM).

Let's say I created some OccupancyGrid within the map (with center on some GPS coordinates = initial robot position) and save the map to file. How do I load the map that it is centered on the same GPS coordinates it was created?

Because, as far as I get, map-odom correspond to the inital position of robot. That means, if phisically my robot starts not on the same coordinates as when the map was created, the loaded map will be centered automatically on theese new coordinates. And I want it to be attached to the ground GPS coordinates independing from the robot initial position.

Actually the question is how do I load a map on specific GPS-centered coordinates?

Thanks!