Application programming interface for prefetching map data

• US 8,849,942 B1
• Filed: 08/21/2012
• Issued: 09/30/2014
• Est. Priority Date: 07/31/2012
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Foster, Andrew, Wang, Zheng, Hearnden, David
• Primary Examiner(s): Nguyen, Tu
• Application Number:
  US13/590,931
• Time in Patent Office: 770 Days
• Field of Search: 709/213
• US Class Current: 709/213
• CPC Class Codes: G06F 12/0862 with prefetch
• CPC Class Codes: G06F 16/29 Geographical information databases
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

An API for prefetching map data receives a prefetch request for an indicated geographic area from a software application. In response, the API retrieves map data corresponding to the indicated geographic area from a map data provider and stores the map data in a map data cache without causing a digital map based on the map data to be displayed on the display device. The map data cache is accessible to the software application only via the API. Subsequently to storing the map data in the map data cache, the API receives a request to render the digital map from the software application and, in response to the request to render the map image, renders the map image for display on a display device using the map data stored in the map data cache.

Claims

1. A non-transitory computer-readable medium storing instructions thereon that implement an application programming interface (API) for prefetching map data on a computing device having a processor and a display device, wherein the computing device is configured to communicate with a map data provider via a communication network, and wherein the API, when invoked in a software application executed on the processor, is configured to:

receive a prefetch request for an indicated geographic area from the software application;

in response to the prefetch request;

(i) retrieve map data corresponding to the indicated geographic area from the map data provider, and (ii) store the map data in a map data cache without causing a digital map based on the map data to be displayed on the display device, wherein the map data cache is accessible to the software application only via the API;

subsequently to storing the map data in the map data cache, receive a request to render the digital map from the software application; and

in response to the request to render the digital map, render the digital map using the map data stored in the map data cache, wherein the digital map is displayed on the display device.

2. The non-transitory computer-readable medium of claim 1, wherein the prefetch request specifies a polyline interconnecting a plurality of geographic locations, and wherein the indicated geographic area is within a fixed radius of the polyline.

3. The non-transitory computer-readable medium of claim 2, wherein the prefetch request further specifies the radius.

4. The non-transitory computer-readable medium of claim 2, wherein the retrieved map data includes a plurality of discrete map elements in a vector graphics format, and wherein the API is configured to retrieve only map elements that represent physical entities at least partially disposed within a fixed radius of the polyline.

5. The non-transitory computer-readable medium of claim 1, wherein the prefetch request indicates a first geographic location and a second geographic location, and wherein the API is configured to retrieve map data for locations disposed within a fixed radius of a route from the first geographic location to the second geographic location.

6. The non-transitory computer-readable medium of claim 1, wherein the prefetch request indicates a single point corresponding to a geographic location;

and wherein the map data is retrieved for areas disposed within a fixed radius of the single point.

7. The non-transitory computer-readable medium of claim 1, wherein the prefetch request indicates a shape that encloses the indicated geographic area.

8. The non-transitory computer-readable medium of claim 1, wherein the retrieved map data is in a raster image format.

9. The non-transitory computer-readable medium of claim 1, wherein the API is provided as a function of an operating system (OS) for use by software applications native to the OS.

10. A method for prefetching map data in computing device including a memory, a processor, and a display device, the method comprising:

allocating a portion of the memory for use as a map data cache, wherein the map data cache stores map data received from a map data provider via a communication network, including preventing software applications being executed by the processor from accessing the map data cache; and

providing an application programming interface (API) for use by the software applications, including;

in response to the API being invoked for prefetching map data, (i) retrieving map data for an indicated geographic area and (ii) storing the map data in the map data cache, wherein a digital map based on the map data is not displayed on the display device in response to the API being invoked for prefetching the map data, and

in response to the API being subsequently invoked for displaying the prefetched map data, (i) retrieving the map data from the map data cache and (ii) generating a digital map using the map data for display on the display device.

11. The method of claim 10, further comprising providing an operating system (OS) for use on a portable computing device, wherein the API is for use by software applications native to the OS.

12. The method of claim 10, wherein:

retrieving the map data in response to the API being invoked for prefetching map data includes receiving the map data via a wireless communication network, and

no wireless network coverage is available when the API being subsequently invoked for displaying the prefetched map data.

13. The method of claim 10, wherein:

retrieving the map data in response to the API being invoked for prefetching map data includes receiving the map data via a first wireless communication network, and

the API being subsequently invoked for displaying the prefetched map data when the computing device roams onto a second wireless communication network.

14. The method of claim 10, wherein the API is configured to receive a description of a polyline interconnecting a plurality of geographic locations, and wherein the indicated geographic area is within a fixed radius of the polyline.

15. The method of claim 14, wherein the retrieved map data is in a vector graphics format and corresponds to a certain zoom level, wherein the digital map is made of a plurality of map tiles of equal size associated with the zoom level, and wherein retrieving the map data for the indicated geographic area includes:

retrieving a first map element that corresponds to a first physical entity disposed within the fixed radius of the polyline, and

not retrieving a second map element that corresponds to a second physical entity disposed outside the fixed radius of the polyline,

wherein the first map element and the second map element are mapped to a same map tile.

16. The method of claim 10, wherein the API is configured to receive a description of a shape that encloses the indicated geographic area.

17. The method of claim 10, wherein the API is configured to receive a description of a single point corresponding to a geographic location;

and wherein the map data is retrieved for areas disposed within a fixed radius of the single point.

18. A mobile device configured to communicate via a wireless communication link, the mobile device comprising:

a processor;

a display device;

a network interface communicatively coupled to the wireless communication link;

a memory communicatively coupled to the processor;

a map data cache disposed in the memory, wherein the map data cache is not accessible to software applications executing on the mobile device via read or write operations;

instructions stored in the memory that implement an application programming interface (API) for prefetching map data, wherein the API, when invoked by a software application executing on the mobile device, is configured to;

in response to receiving a prefetch request indicating a geographic area from a software application executing on the mobile device, (i) retrieve map data for the indicated geographic area via the network interface and (ii) store the map data in the map data cache, wherein a digital map based on the map data is not displayed on the display device in response to receiving the prefetch request, and

in response to subsequently receiving a request to render the digital map from the software application, cause the digital map to be displayed on the display device using the map data stored in the map data cache.

19. The mobile device of claim 18, wherein the instructions that implement the API are first instructions, the mobile device further comprising:

second instructions stored in the memory that, when executed on the mobile device, implement an operating system (OS) that provides a plurality of functions invoked by the software applications executing on the mobile device, wherein the plurality of functions include the read and write operations;

wherein the software application that invokes the API for prefetching map data is native to the OS.

20. The mobile device of claim 19, wherein the software application is a web browser application.

21. The mobile device of claim 19, wherein the OS allocates a portion of the memory for use as the map data cache.

22. The mobile device of claim 19, wherein the prefetch request specifies a polyline interconnecting a plurality of geographic locations, and wherein the indicated geographic area is within a fixed radius of the polyline.

23. The mobile device of claim 19, wherein the prefetch request specifies a shape that encloses the indicated geographic area.