Map rendering using interpolation of style parameters across zoom levels

Abstract

A viewing window of a map surface is determined, at a certain zoom level corresponding to the magnification of the map surface. A first set of style parameters for applying to a feature of the map surface, where the feature is described in a vector format using several interconnected vertices, is determined. The first set of style parameters corresponds to a first zoom level of the viewing window, and the first zoom level corresponds to a first magnification. A second set of style parameters for the feature is also determined, where the second set of style parameters corresponds to a second zoom level of the viewing window, and where the second zoom level corresponds to a second magnification. A third set of style parameters for displaying the feature is determined by interpolating between the first set of style parameters and the second set of style parameters.

What is claimed: 
     
         1 . A method for rendering a map on a display device, the method comprising:
 determining, by one or more processing devices, a viewing window of a map surface, at a certain zoom level corresponding to the magnification of the map surface;   determining, by the one or more processing devices, a first set of style parameters for applying to a feature of the map surface, wherein the feature is described in a vector format using a plurality of interconnected vertices, wherein the first set of style parameters corresponds to a first zoom level of the viewing window, and wherein the first zoom level corresponds to a first magnification;   determining, by the one or more processing devices, a second set of style parameters for the feature, wherein the second set of style parameters corresponds to a second zoom level of the viewing window, and wherein the second zoom level corresponds to a second magnification;   determining, by the one or more processing devices, a third set of style parameters by interpolating between the first set of style parameters and the second set of style parameters, including interpolating at least color and outline width; and   displaying the feature using the third set of style parameters.   
     
     
         2 . The method of  claim 1 , wherein the third set of style parameters corresponds with a third zoom level having a third magnification between the first magnification and the second magnification. 
     
     
         3 . The method of  claim 1 , wherein interpolating between the first set of style parameters and the second set of style parameters includes interpolating an outline dashing pattern. 
     
     
         4 . The method of  claim 1 , wherein interpolating the color includes interpolating text color. 
     
     
         5 . The method of  claim 1 , wherein interpolating the color includes interpolating interior color. 
     
     
         6 . The method of  claim 1 , wherein determining the third set of style parameters includes using an interpolation parameter to interpolate between at least the first set of style parameters at the first magnification and the second set of style parameters at the second magnification, the method further comprising:
 changing the interpolation parameter over time; and   repeating the acts of i) determining the third set of style parameters, and ii) displaying the first feature using the third set of style parameters, in response to changing the interpolation parameter over time.   
     
     
         7 . The method of  claim 1 , wherein the first set of style parameters and the second set of style parameters are stored in a lookup table associated with the plurality of vertices. 
     
     
         8 . The method of  claim 7 , wherein the first and the second set of style parameters are located in a first and a second lookup table, respectively, each of the lookup tables associated with a different zoom level at a different magnification. 
     
     
         9 . The method of  claim 1 , wherein determining the first set and the second set of style parameters includes retrieving only a subset of style parameters available for retrieval based on a style attribute setting associated with each style parameter indicating whether the style parameter is designated for interpolation. 
     
     
         10 . The method of  claim 1 , wherein determining the first set and the second set of style parameters includes retrieving only a subset of the style parameters available for retrieval based on a priority attribute associated with each style parameter and whether a current available bandwidth is above a threshold. 
     
     
         11 . A computer device comprising:
 a communications network interface;   one or more processors;   a display device coupled to the one or more processors;   one or more non-transitory memories, coupled to the one or more processors, storing instructions that, when executed on the one or more processors, cause the computer device to:
 determine a viewing window of a map surface, at a certain zoom level corresponding to the magnification of the map surface, 
 determine a first set of style parameters for applying to a feature of the map surface, wherein the feature is described in a vector format using a plurality of interconnected vertices, wherein the first set of style parameters corresponds to a first zoom level of the viewing window, and wherein the first zoom level corresponds to a first magnification; 
 determine a second set of style parameters for the feature, wherein the second set of style parameters corresponds to a second zoom level of the viewing window, and wherein the second zoom level corresponds to a second magnification; 
 determine a third set of style parameters by interpolating between the first set of style parameters and the second set of style parameters, including interpolate at least color and outline width; and 
 display the feature using the third set of style parameters. 
   
     
     
         12 . The computer device of  claim 11 , wherein the third set of style parameters corresponds with a third zoom level having a third magnification between the first magnification and the second magnification. 
     
     
         13 . The computer device of  claim 11 , wherein to interpolate between the first set of style parameters and the second set of style parameters, the instructions cause the computer device to interpolate an outline dashing pattern. 
     
     
         14 . The computer device of  claim 11 , wherein the instructions cause the computer device to interpolate text color. 
     
     
         15 . The computer device of  claim 11 , wherein the instructions cause the computer device to interpolate interior color. 
     
     
         16 . The computer device of  claim 11 , wherein to determine the third set of style parameters, the instructions cause the computing device to use an interpolation parameter to interpolate between at least the first set of style parameters at the first magnification and the second set of style parameters at the second magnification, and wherein the instructions further cause the computer device to:
 change the interpolation parameter over time; and   repeat the acts of i) determining the third set of style parameters, and ii) displaying the first feature using the third set of style parameters, in response to changing the interpolation parameter over time.   
     
     
         17 . The computer device of  claim 11 , wherein the first set of style parameters and the second set of style parameters are stored in a lookup table associated with the plurality of vertices. 
     
     
         18 . The computer device of  claim 17 , wherein the first and the second set of style parameters are located in a first and a second lookup table, respectively, each of the lookup tables associated with a different zoom level at a different magnification. 
     
     
         19 . The computer device of  claim 11 , wherein to determine the first set and the second set of style parameters, the instructions cause the computer device to retrieve only a subset of style parameters available for retrieval based on a style attribute setting associated with each style parameter indicating whether the style parameter is designated for interpolation. 
     
     
         20 . The computer device of  claim 11 , wherein to determine the first set and the second set of style parameters, the instructions cause the computer device to retrieve only a subset of the style parameters available for retrieval based on a priority attribute associated with each style parameter and whether a current available bandwidth is above a threshold.