Representation of digital map styling properties across zoom levels

Abstract

A process and system allow for visually representing style layer properties of a digital map across various zoom levels. From a style sheet for a digital map, a plurality of style layer properties for a style layer corresponding to the digital map are determined for rendering in the form of a visual map, including various property values for different zoom levels. From these, a zoom level function is generated between pairs of the values for a particular style layer property, by assigning property values (a continuous range or finite set) between the first property value and the second property value in the pair. A visual map based on vector map tiles rendered according to the zoom level function is displayed according to the selected zoom level. As values are changed, the visual map is updated to reflect the changes.

What is claimed is: 
     
         1 . A method of representing a style layer property at various zoom levels, comprising:
 maintaining a style sheet for a digital map, wherein the style sheet comprises a style layer including a style layer property and corresponds to a data layer that is separate from the style layer and represents a map feature;   for the style layer:
 receiving a first property value for a first zoom level of the style layer property; 
 receiving a second property value for a second zoom level of the style layer property; and 
 generating a zoom level function for the style layer property that assigns a continuous range of property values between the first property value and the second property value to a continuous range of zoom levels between the first zoom level and the second zoom level; and 
   sending for display the digital map at a particular zoom level, wherein the digital map comprises the map feature visually represented within the digital map based on the generated zoom level function.   
     
     
         2 . The method of  claim 1 , further comprising receiving selection of the style layer from a plurality of style layers of the maintained style sheet. 
     
     
         3 . The method of  claim 1 , further comprising displaying the style layer property for the style layer. 
     
     
         4 . The method of  claim 1 , further comprising receiving user input, wherein the first property value is based on the received user input. 
     
     
         5 . The method of  claim 1 , further comprising receiving selection of a zoom level control. 
     
     
         6 . The method of  claim 1 , further comprising:
 receiving selection of a zoom level control; and   generating a zoom level step function for the style layer property that assigns a finite set of property values between the first property value and the second property value to the continuous range of zoom levels between the first zoom level and the second zoom level.   
     
     
         7 . The method of  claim 1 , further comprising:
 receiving user input specifying a display zoom level of a plurality of zoom levels between the first zoom level and the second zoom level;   determining, based on the generated zoom level function, a property value for the style layer property at the display zoom level; and   displaying the property value for the style layer property at the display zoom level.   
     
     
         8 . The method of  claim 1 , further comprising receiving user input specifying a rate of change value, wherein a curvature of the zoom level function is based on the specified rate of change value. 
     
     
         9 . The method of  claim 1 , further comprising:
 receiving user input specifying a third property value to associate with a third zoom level for the style layer property; and   generating an additional zoom level function for the style layer property that assigns an additional range of property values between the second property value and the third property value to an additional range of zoom levels between the second zoom level and the third zoom level.   
     
     
         10 . The method of  claim 9 , further comprising:
 receiving user input specifying a first rate of change value, wherein a curvature of the zoom level function is based on the first rate of change value; and   receiving user input specifying a second rate of change value, wherein a curvature of the additional zoom level function is based on the second rate of change value.   
     
     
         11 . The method of  claim 1 , further comprising:
 based on an order of the first zoom level value and the second zoom level value for the style layer property, displaying the first property value in association with the first zoom level value and the second property value in association with the second zoom level value; and   in response to receiving user input editing the property value for the style layer property to add a third zoom level between the first and second zoom level values:
 sorting the first, second, and third zoom levels into numerical order; and 
 re-displaying the first, second, and third zoom levels based on the sorting. 
   
     
     
         12 . The method of  claim 11 , further comprising, in response to receiving user input editing the property value for the style layer property to add a third zoom level between the first and second zoom level values:
 generating a first partial zoom level function for the style layer property that assigns a range of property values between the first property value and the third property value to the range of zoom levels between the first zoom level and the third zoom level; and   generating a second partial zoom level function for the style layer property that assigns a range of property values between the third property value and the second property value to the range of zoom levels between the third zoom level and the second zoom level.   
     
     
         13 . The method of  claim 1 , wherein the style sheet comprises the style layer and a second style layer, which each corresponds to one style type, the method further comprising:
 receiving a selection of the style layer and the second style layer;   receiving a third property value for a third zoom level of the style layer property of the selected two style layers of the one style layer type;   receiving a fourth property value for a fourth zoom level of the style layer property of the selected style layers of the one style layer type;   generating a second zoom level function for the style layer property of the selected two style layers of the one style layer type that assigns a continuous range of property values between the third property value and the fourth property value to a continuous range of zoom levels between the third zoom level and the fourth zoom level; and   sending for display the digital map at another zoom level, wherein the digital map is visually represented within the digital map based on the generated second zoom level function.   
     
     
         14 . The method of  claim 1 , wherein at least the style layer property in the maintained style sheet for the digital map is defined by a first organization, the method further comprising:
 maintaining a second style sheet comprising a style layer that comprises a style layer property defined by a second organization different from the first organization,   wherein the style layer property defined by the second organization differs from the corresponding style layer property in the maintained style sheet defined by the first organization.   
     
     
         15 . The method of  claim 1 , wherein the style sheet is stored as a document separate from the data layer. 
     
     
         16 . A system, comprising:
 one or more processors; and   a non-transitory computer-readable storage medium storing computer program instructions executable by the one or more processors to perform operations, the operations comprising:
 maintaining a style sheet for a digital map, wherein the style sheet comprises a style layer including a style layer property and corresponds to a data layer that is separate from the style layer and represents a map feature; 
 for the style layer:
 receiving a first property value for a first zoom level of the style layer property; 
 receiving a second property value for a second zoom level of the style layer property; and 
 generating a zoom level function for the style layer property that assigns a continuous range of property values between the first property value and the second property value to a continuous range of zoom levels between the first zoom level and the second zoom level; and 
 
 sending for display the digital map at a particular zoom level, wherein the digital map comprises the map feature visually represented within the digital map based on the generated zoom level function. 
   
     
     
         17 . The system of  claim 16 , the operations further comprising:
 in response to receiving selection of a zoom level control corresponding to the style layer property, generating a zoom level step function for the style layer property that assigns a finite set of property values between the first property value and the second property value to the range of zoom levels between the first zoom level and the second zoom level.   
     
     
         18 . The system of  claim 16 , the operations further comprising:
 receiving user input specifying a display zoom level of a plurality of zoom levels between the first zoom level and the second zoom level;   determining, based on the generated zoom level function, a property value for the style layer property at the display zoom level; and   displaying the property value for the style layer property at the display zoom level.   
     
     
         19 . The system of  claim 16 , the operations further comprising:
 receiving user input specifying a rate of change value, wherein a curvature of the zoom level function is based on the specified rate of change value.   
     
     
         20 . The system of  claim 19 , operations further comprising:
 in response to receiving user input editing the property value to add a third zoom level between the first and second zoom level values:
 generating a first partial zoom level function for the style layer property that assigns a range of property values between the first property value and the third property value to the range of zoom levels between the first zoom level and the third zoom level; and 
 generating a second partial zoom level function for the style layer property that assigns a range of property values between the third property value and the second property value to the range of zoom levels between the third zoom level and the second zoom level.