In some implementations, a system can optimize offline map data updates. For example, a server device in the system can determine a metric for identifying map data objects based on attributes of the map data objects. The server device can then generate a quadtree that stores the map data objects in nodes of the quadtree based on the metric. When processing an update to the map data stored at the server device, the server device can generate update data describing the updates for each node in the quadtree based on a binary difference algorithm and/or a semantic difference algorithm. The server device can select the algorithm based on which algorithm results in the smallest compressed size of the update data.