Pre-fetching map tile data along a route

• US 9,111,397 B2
• Filed: 06/24/2014
• Issued: 08/18/2015
• Est. Priority Date: 12/12/2011
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Kalai, Iljya, Siliski, Michael, Morrison, Jerry, Ito, Keith, Miller, Andrew
• Primary Examiner(s): Tung, Kee M
• Assistant Examiner(s): CHEN, FRANK S
• Application Number:
  US14/313,727
• Publication Number:
  US 20140306991A1
• Time in Patent Office: 420 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01C 21/34 Route searching; Route guidance
• CPC Class Codes: G01C 21/367 Details, e.g. road map scale, orientation, zooming, illumination, level of detail, scrolling of road map or positioning of current position marker
• CPC Class Codes: G01C 21/3881 Tile-based structures
• CPC Class Codes: G01C 21/3889 Transmission of selected map data, e.g. depending on route
• CPC Class Codes: G01C 21/3896 Transmission of map data from central databases
• CPC Class Codes: G06F 16/29 Geographical information databases
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G06T 1/60 Memory management
• CPC Class Codes: G06T 11/60 Editing figures and text; Combining figures or text
• CPC Class Codes: G06T 17/05 Geographic models

Abstract

The present application describes techniques for fetching map data as a selected subset of entire map data available by selecting map data tiles corresponding to an area that encompasses a route. An amount of map data accessed may be adjusted based on a priority assigned to areas or points along the route. A sequence of map data may be accessed based on a priority assigned to sets of map data.

Claims

1. A computer-implemented method for pre-fetching map data for a mapping application, comprising:

initiating, using one or more processors, a first routing function to generate a route, the route defined by an origin, a destination, and a set of paths connecting the origin to the destination;

determining, using the one or more processors, a first set of map data tiles of a first zoom level corresponding to a first map surface area, the first set of map data tiles including the origin;

determining, using the one or more processors, a second set of map data tiles of the first zoom level corresponding to a second map surface area, the second set of map tiles including the destination;

determining, using the one or more processors, a set of points along the route between the origin and the destination and a third set of map tiles of the first zoom level corresponding to a set of map surface areas including the set of points along the route;

determining, using the one or more processors, a fourth set of map data tiles of a second zoom level, wherein the fourth set of map data tiles include at least one of the origin, the destination, or the set of map surface areas including the set of points along the route, and the fourth set of map data tiles provides a different magnification of corresponding map areas than the first, the second, or the third map data tiles;

retrieving, using the one or more processors, from an external map database the first, the second, the third and the fourth sets of map data tiles;

storing, using the computer, the first, the second, the third and the fourth set of map data tiles in a local memory;

initiating, using the one or more processors, a first rendering function, to display at least a portion of the route at the first zoom level using at least one of the first, the second, the third and the fourth sets of map data tiles stored in the local memory; and

initiating, using the one or more processors, a second rendering function, to display at least a portion of the route at the second zoom level using the fourth set of map data tiles stored in the local memory instead of map data tiles of the external map database, wherein the fourth set of map data tiles is retrieved from the external map database and stored in the local memory prior to initiating the first rendering function.

2. The computer-implemented method of claim 1, wherein points along the route closer to the origin and destination have shorter radii than points along the route further from the origin and destination.

3. The computer-implemented method of claim 1, wherein one of the set of points along the route corresponds to a location on the route of high priority, and wherein a map tile radii corresponding to the point of high priority is larger than a point of low priority.

4. The computer-implemented method of claim 1, wherein determining, using the one or more processors, the first and second sets of map data tiles is based on an allocated memory size of the client device.

5. The computer-implemented method of claim 1, further including determining, using the one or more processors, that at least one of a first tile radius and a second tile radius is larger when a viewing window is centered on one of the first tile radius or the second tile radius.

6. The computer-implemented method of claim 1, wherein the fourth set of map data tiles are defined by a point along the route that is within a threshold distance of a viewing window center.

7. The computer-implemented method of claim 1, further including:

determining, using the one or more processors, a tile radius associated with a point of interest not along the route, wherein the tile radius defines a fifth set of map data tiles corresponding to a location not along the route with high priority,

accessing, using the one or more processors, from the map database, the fifth set of map data tiles, and

storing, using the one or more processors, the fifth set of map data tiles in the local memory, wherein initiating, using the one or more processors, the second rendering function uses the fifth set of map data tiles.

8. The computer-implemented method of claim 1, further including determining a first tile radius and a second tile radius are smaller when a bandwidth of the client device is below a threshold than when the bandwidth is above the threshold, and determining the first tile radius and the second tile radius are smaller when a processor load of the client device is above a threshold than when the processor load is below the threshold.

9. A computer device comprising:

a communications network interface;

one or more processors;

one or more memories coupled to the one or more processors;

a display device coupled to the one or more processors;

wherein the one or more memories include computer executable instructions stored therein that, when executed by the one or more processors, cause the one or more processors to;

initiate a first routing function to generate a route, the route defined by an origin, a destination, and a set of paths connecting the origin to the destination;

determine a first set of map data tiles of a first zoom level corresponding to a first map surface area, the first set of map data tiles including the origin;

determine a second set of map data tiles of the first zoom level corresponding to a second map surface area, the second set of map tiles including the destination;

determine a set of points along the route between the origin and the destination and a third set of map tiles of the first zoom level corresponding to a set of map surface areas including the set of points along the route;

determine a fourth set of map data tiles of a second zoom level, wherein the fourth set of map data tiles include at least one of the origin, the destination, or the set of map surface areas including the set of points along the route, and the fourth set of map data tiles provides a different magnification of corresponding map areas than the first, the second, or the third map data tiles;

retrieve from an external map database the first, the second, the third and the fourth sets of map data tiles;

store the first, the second, the third and the fourth set of map data tiles in a local memory;

initiate a first rendering function to display at least a portion of the route at the first zoom level using at least one of the first, the second, the third and the fourth sets of map data tiles stored in the local memory; and

initiate a second rendering function to display at least a portion of the route at the second zoom level using the fourth set of map data tiles stored in the local memory instead of map data tiles of the external map database, wherein the fourth set of map data tiles is retrieved from the external map database and stored in the local memory prior to initiating the first rendering function.

10. The computer device of claim 9, wherein points along the route closer to the origin and destination have shorter radii than points along the route further from the origin and destination.

11. The computer device of claim 9, wherein one of the set of points along the route corresponds to a location on the route of high priority, and wherein a map tile radii corresponding to the point of high priority is larger than a point of low priority.

12. The computer device of claim 9, wherein the instructions to determine the first and second sets of map data tiles are based on an allocated memory size of the client device.

13. The computer device of claim 9, further including instructions to determine that at least one of a first tile radius and a second tile radius is larger when a viewing window is centered on one of the first tile radius or the second tile radius.

14. The computer device of claim 9, wherein the fourth set of map data tiles are defined by a point along the route that is within a threshold distance of a viewing window center.

15. The computer device of claim 9, further including instructions to:

determine a tile radius associated with a point of interest not along the route, wherein the tile radius defines a fifth set of map data tiles corresponding to a location not along the route with high priority;

access, from the map database, the fifth set of map data tiles; and

store the fifth set of map data tiles in the local memory, wherein instructions to initiate the second rendering function uses the fifth set of map data tiles.

16. The computer device of claim 9, further including instructions to determine that a first tile radius and a second tile radius are smaller when a bandwidth of the client device is below a threshold than when the bandwidth is above the threshold, and instructions to determine that the first tile radius and the second tile radius are smaller when a processor load of the client device is above a threshold than when the processor load is below the threshold.

17. A method for pre-fetching map data for generating digital maps at client devices, the method comprising:

determining, by one or more processors, a path connecting a first geographic location defining an origin to a second geographic destination defining a destination;

fetching, by the one or more processors, map data from an external map database to a local memory of a client device prior to detecting a need to use the map data for rendering at the client device, wherein the map data is usable for rendering digital maps of geographic areas disposed along the path, including fetching map data for rendering digital maps for one the geographic areas disposed along the path at two different zoom levels; and

generating respective digital maps of the one the geographic areas at the two different zoom levels using the pre-fetched map data stored in the local memory.

18. The method of claim 17, wherein fetching the map data prior to detecting a need to use the map data for rendering at the client device includes fetching the map data prior to a user of the client device activating a function for using the map data.

19. The method of claim 17, wherein the geographic area for which the map data at the two different zoom levels was fetched includes the origin.

20. The method of claim 17, wherein the geographic area for which the map data at the two different zoom levels was fetched includes the destination.