A method for efficiently transmitting image map data to client devices, the method comprising: receiving, from a client device, a request for map data for rendering a digital map of a certain geographic area; selecting map data for rendering the digital map; generating multiple map image layers using the selected map data, each covering the geographic area, including generating (i) a first map image layer including a first type of geographic data and having a first resolution, and (ii) a second map image layer including a second type of geographic data and having a second resolution, wherein: the first map image layer is a POI/label map image layer, the first type of geographic data relates to points of interest and/or labels, the second map image layer is a base map image layer, the second type of geographic data relates to large geological formations, and the second resolution is lower than the first resolution; and transmitting the multiple map image layers to the client device via a communication network for generating a single digital map of the geographic area, wherein the client device: stores, in a memory of the client device, the first map image layer as a first map tile and the second map image layer as a second map tile; and applies a first caching and purging policy for the first map image layer and a second caching and purging policy for the second map image layer based on the type of information included in the first map tile and the second map tile, respectively, wherein the second caching and purging policy defines a storage time for the second map tile that is longer relative to a storage time defined by the first caching and purging policy for the first map tile, so that the second map image layer can be reused when zooming the digital map to a level unavailable at the client device. receiving, from a client device, a request for map data for rendering a digital map of a certain geographic area; selecting map data for rendering the digital map; generating multiple map image layers using the selected map data, each covering the geographic area, including generating (i) a first map image layer including a first type of geographic data and having a first resolution, and (ii) a second map image layer including a second type of geographic data and having a second resolution, wherein: the first map image layer is a POI/label map image layer, the first type of geographic data relates to points of interest and/or labels, the second map image layer is a base map image layer, the second type of geographic data relates to large geological formations, and the second resolution is lower than the first resolution; and the first map image layer is a POI/label map image layer, the first type of geographic data relates to points of interest and/or labels, the second map image layer is a base map image layer, the second type of geographic data relates to large geological formations, and the second resolution is lower than the first resolution; and transmitting the multiple map image layers to the client device via a communication network for generating a single digital map of the geographic area, wherein the client device: stores, in a memory of the client device, the first map image layer as a first map tile and the second map image layer as a second map tile; and applies a first caching and purging policy for the first map image layer and a second caching and purging policy for the second map image layer based on the type of information included in the first map tile and the second map tile, respectively, wherein the second caching and purging policy defines a storage time for the second map tile that is longer relative to a storage time defined by the first caching and purging policy for the first map tile, so that the second map image layer can be reused when zooming the digital map to a level unavailable at the client device. stores, in a memory of the client device, the first map image layer as a first map tile and the second map image layer as a second map tile; and applies a first caching and purging policy for the first map image layer and a second caching and purging policy for the second map image layer based on the type of information included in the first map tile and the second map tile, respectively, wherein the second caching and purging policy defines a storage time for the second map tile that is longer relative to a storage time defined by the first caching and purging policy for the first map tile, so that the second map image layer can be reused when zooming the digital map to a level unavailable at the client device.