Rendering map images using modifications of non-raster map data

A tangible non-transitory computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause the one or more processors to:

• generate, in response to a request received from a client device, first map data in a non-raster format for a selected geographic region, wherein the first map data is interpretable at the client device to generate a first map image in a raster format and display the first map image at the client device;
• cause the first map data to be transmitted to the client device via a communication network;
• receive, from the client device, an indication that a second map image for the selected geographic region is to be rendered at the client device;
• wherein:
• the first map image corresponds to a first map type, and the second map image corresponds to a second map type, and
• the first map type is one of basic map, terrain map, transit map, and traffic map, and the second map type is another one of basic map, terrain map, transit map, and traffic map;
• identify second map data required to generate the second map image,
• determine a difference between the first map data and the second map data, wherein the first map data and the second map data are partially identical;
• generate a modification indication descriptive of one or more modifications to the map data for transforming the first map image into the second map image;
• and
• cause the modification indication to be transmitted to the client device via a communication network for rendering and displaying the second map image in the raster format at the client device using at least a portion of the map data and the modification indication.

A method in a computing device for generating map images, wherein the computing device communicates with a map via a communication network, the method comprising:

• receiving, via a user interface of the computing device, a selection of a first map type, a geographic region, and a zoom level;
• receiving, via a communication network, a plurality of vector descriptors for rendering a first map image for the selected geographic region and the first map type at the selected zoom level, wherein each vector descriptor indicates a geometry of a respective map element in accordance with a vector graphics format, and wherein each map element illustrates a respective physical entity in the geographic region;
• rendering the first map image using the plurality of vector descriptors;
• causing the first map image to be displayed via the user interface of the computing device;
• receiving, via the user interface, a selection of a second map type;
• receiving, via the communication network, a modification indication that indicates a modification of the plurality of vector descriptors for rendering a second map image for the second map type and the previously selected geographic region at the previously selected zoom level;
• rendering the second map image using at least some of the plurality of vector descriptors and the modification indication;
• and
• causing the second map image to be displayed via the user interface.

A computing device operating in a communication network, the computing device comprising:

• a processor;
• a memory coupled to the processor;
• a network interface for communicating via the communication network;
• a display device coupled to the processor;
• a first routine, stored in the memory, that executes on the processor to receive a selection of a first map type and a geographic region from a user interface of the computing device, wherein the first map type is one of basic map, terrain map, transit map, and traffic map;
• a second routine, stored in the memory, that executes on the processor to cause a request for map data corresponding to the selected geographic region to be transmitted to a map server via the network interface;
• a third routine, stored in the memory, that executes on the processor to render a first map image using a plurality of vector descriptors received via the network interface in response to the request and cause the first map image to be displayed on the display device, wherein the plurality of vector descriptors describes a plurality of map elements according to a vector graphics format, and wherein each of the plurality map elements illustrates a respective physical entity in the selected geographic region;
• a fourth routine, stored in the memory, that executes on the processor to receive a selection of a second map type for the same geographic region, wherein the second map type is one of basic map, terrain map, transit map, and traffic map, and wherein the second map type is different from the first map type;
• a fifth routine, stored in the memory, that executes on the processor to cause a request for modification data corresponding to the selected geographic region and the second map type to be transmitted to the map server via the network interface, wherein the map server determines a difference between a description of the selected geographic region according to the first map type and a description of the selected geographic region according to the second map type in a vector graphics format in response to the request for modification data;
• and
• a sixth routine, stored in the memory, that executes on the processor to render a second map image using at least some of the plurality of vector descriptors and the modification data and cause the second map image to be displayed on the display device.