The subject matter of this specification can be embodied in, among other things, a system includes a map store, a map server, and a content server. The map server identifies a set of content items in which each content item is associated with a geographic location that is presented in a portion of a map, determines, for a given content item, an adjusted value of a given content item based at least in part on a base value for the content given item and a set of adjustment factors for one or more other content items in the set of content items, selects content items from the set of content items based on the adjusted values, and provides data that present the selected content items on the portion of the map presented at the device.