A method generates map visualizations with multiple map layers. A user selects a data source with geographic data. A device displays a data visualization user interface, including a schema information region with data fields, and shelf regions that defining characteristics for a data visualization. The user selects a first geographic data, and the user interface generates a map data visualization using coordinates associated with the first geographic data field. The visualization includes a first plurality of data marks in a first layer. The user selects a second geographic data field. In response, the user interface displays a new layer icon. Upon activation of the new layer icon by the second geographic data field, the user interface superimposes a second layer over the existing map data visualization to form an updated map data visualization. The second layer includes a second plurality of data marks corresponding to the second geographic data field.