Use of map data difference tiles to iteratively provide map data to a client device

Patent metadata

Field	Value
Publication number	US-9396508-B2
Application number	US-201313895310-A
Country	US
Kind code	B2
Filing date	May 15, 2013
Priority date	May 15, 2013
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

To provide map data for rendering map images corresponding to a selected geographic region at a client device, a map server generates a set of base map tiles having vector descriptors, each of which indicates a geometry of a respective map element, in accordance with a non-raster format for rendering a first map image. The map server, at some point, provides the base map tiles to the client device. Upon receiving an indication that a specific map image for the selected geographic region is to be rendered at the client device, the map server further generates a set of difference map tiles that indicate changes to be made to the set of base map tiles and sends the difference map tiles to the client device for use, along with the set of base map tiles, in rendering the requested specific map image.

First claim

What is claimed is:

1. A computer-implemented method for providing map data to a client device via a communication network, the method comprising:
generating one or more base map tiles, each base map tile including a plurality of vector descriptors for rendering and displaying, at the client device, a first map image for a selected geographic region, wherein the first map image corresponds to a first zoom level, wherein each vector descriptor indicates a geometry of a respective map element in accordance with a vector graphics format, including generating a set of style data defining visual characteristics to be applied to the geometry of at least some of the plurality of vector descriptors;
causing the one or more base map tiles to be transmitted to the client device via the communication network;
receiving an indication that a second map image for the selected geographic region is to be rendered at the client device, wherein the second map image is different from the first map image but includes a region covered by at least one of the base map tiles, and wherein the second map image corresponds to a second zoom level different than the first zoom level;
generating a set of difference map tiles that define a difference between the first map image and the second map image to be displayed, including specifying map features associated with the second zoom level, the set of difference map tiles including one or more descriptors, each of which corresponds to a change in a map element as rendered in the second map image as compared to the first map image, including generating a different set of style data defining different visual characteristics to be applied to the geometry of the at least some of the plurality of vector descriptors; and
causing the set of difference map tiles to be transmitted to the client device via the communication network for rendering and displaying the second map image using at least some of the information in the one or more base map tiles and the set of difference map tiles.

2. The method of claim 1 , wherein generating the set of difference map tiles includes:
identifying a map element that is not included as a part of the first map image but is to be rendered as a part of the second map image;
providing, in the set of difference map tiles, a vector descriptor corresponding to the identified map element; and
providing, in the set of difference map tiles, an add indication corresponding to the identified map element to indicate that the identified map element is to be rendered in the second map image using the provided vector.

3. The method of claim 2 , wherein generating the set of difference map tiles further includes providing, in the set of difference map tiles, a depth indication corresponding to the identified map element, wherein the depth indication indicates an order in which the identified map element is to be rendered within an area that also includes at least one other map element, and wherein the identified map element and the at least one other map element overlap.

4. The method of claim 1 , wherein generating the set of difference map tiles includes:
identifying a map element that is included as a part of the first map image but is not to be rendered as a part of the second map image, wherein the identified map element corresponds to one of the plurality of vector descriptors transmitted to the client device as part of one of the base map tiles for the first map image;
providing, in the set of difference map tiles, an identifier of the one of the plurality of vector descriptors that corresponds to the identified map element; and
providing, in the set of difference map tiles, a remove indication to indicate that the identified map element is not to be rendered in the second map image.

5. The method of claim 1 , wherein generating a set of style data for the one or more base map tiles includes generating a style table for each of the one or more base map tiles and wherein generating the set of difference map tiles includes generating a new style table for each of the set of difference map tiles that is different than the style tables for the base map tiles.

6. The method of claim 1 , wherein generating the one or more base map tiles includes obtaining the base map tiles from a first database, and wherein generating the set of difference map tiles includes obtaining a set of change data from a second database defining a new map view of the geographical region defined for the one or more base map tiles and using the set of change data from the second database to generate the set of difference map tiles.

7. The method of claim 1 , wherein generating the one or more base map tiles includes generating a plurality of base map tiles for a geographical region and wherein generating the set of difference map tiles includes generating a separate difference map tile for each of the plurality of base map tiles.

8. A computer-implemented method for providing map data to a client device via a communication network, the method comprising:
generating one or more base map tiles, each base map tile including a plurality of vector descriptors associated with a first map image for a selected geographic region, wherein each vector descriptor indicates a geometry of a respective map element in accordance with a vector graphics format, including generating a set of style data defining visual characteristics to be applied to the geometry of at least some of the plurality of vector descriptors;
generating a set of difference map tiles that define a difference between the first map image and the second map image to be displayed at a client device, the set of difference map tiles including one or more descriptors, each of which corresponds to a change in a map element as rendered in the second map image as compared to the first map image, including generating a different set of style data defining different visual characteristics to be applied to the geometry of the at least some of the plurality of vector descriptors, including obtaining one or more personalized settings associated with a map request defining a personalized map view and generating a set of difference tiles that implement the personalized map view from the one or more base map tiles;
causing the one or more base map tiles to be transmitted to the client device via the communication network; and
causing the set of difference map tiles to be transmitted to the client device via the communication network for rendering and displaying the second map image using at least some of the information in the one or more base map tiles and the set of difference map tiles.

9. The method of claim 8 , wherein generating the set of difference map tiles includes:
identifying a map element that is not included as a part of the first map image but is to be rendered as a part of the second map image;
providing, in the set of difference map tiles, a vector descriptor corresponding to the identified map element; and
providing, in the set of difference map tiles, an add indication corresponding to the identified map element to indicate that the identified map element is to be rendered in the second map image using the provided vector.

10. The method of claim 8 , wherein generating the set of difference map tiles includes:
identifying a map element that is included as a part of the first map image but is not to be rendered as a part of the second map image, wherein the identified map element corresponds to one of the plurality of vector descriptors transmitted to the client device as part of one of the base map tiles associated with the first map image;
providing, in the set of difference map tiles, an identifier of the one of the plurality of vector descr

Assignees

• Google Inc

Inventors

• Otero Daniel
• Lee Nicholas
• Darpinian James
• Maurer Jennifer

Classifications

• G01C21/3667

  Display of a road map (G01C21/3614 takes precedence; guidance using 3D or perspective road maps G01C21/3635) · CPC title

• G06T1/00 Primary

  General purpose image data processing · CPC title

• G06T9/00 Primary

  Image coding (bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00) · CPC title