Stitching of paths for improved text-on-path rendering of map labels

Abstract

A wireless communications device obtains sets of map data for rendering portions of a map on a display of the device. The map data includes label data for rendering labels on the map for identifying map features. Once the map data is obtained, the wireless device generates a list of all the labels to be rendered on the map, and for each duplicated label in the list, determines whether the map features associated with the duplicated labels connect on the map. If the labels connect, the device then generates a reconstructed map feature and renders a single instance of the label for the map feature. Accordingly, a map feature, such as a path, can be rendered with a single label even if the map data for the map feature, including its associated labels, was transmitted over-the-air as discrete sets of data.

1 . A method of displaying a map on a wireless communications device, the method comprising steps of: 
 obtaining sets of map data for rendering portions of the map on a display of the device, the map data including label data for rendering labels on the map for identifying one or more map features;    generating a list of all the labels to be rendered on the map;    for each duplicated label in the list, determining whether the map features associated with the duplicated labels connect on the map;    generating a reconstructed map feature; and    rendering a single instance of the label for the map feature.    
   
   
       2 . The method as claimed in  claim 1  wherein the step of rendering the single instance of the label comprises a step of rendering the label such that the label is aligned with a middle of the reconstructed map feature.  
   
   
       3 . The method as claimed in  claim 1  wherein the reconstructed map feature is a reconstructed path that is reconstructed from constituent path segments derived from separate sets of map data.  
   
   
       4 . The method as claimed in  claim 3  wherein the step of determining whether the map features associated with the duplicated labels connect on the map comprises a step of determining whether a first endpoint of a first path associated with the duplicated label matches a second endpoint of a second path also associated with the duplicated label.  
   
   
       5 . The method as claimed in  claim 4  wherein the step of rendering the single instance of the label comprises a step of rendering the label midway along the reconstructed path.  
   
   
       6 . The method as claimed in  claim 1  wherein the step of generating the reconstructed map feature comprises steps of: 
 determining a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed map feature; and    reversing the direction of one or more data vectors so that all data vectors in the reconstructed map feature have a common direction.    
   
   
       7 . The method as claimed in  claim 3  wherein the step of generating the reconstructed map feature comprises steps of: 
 determining a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed path; and    reversing the direction of one or more data vectors so that all data vectors corresponding to each constituent path segment in the reconstructed path have a common direction.    
   
   
       8 . The method as claimed in  claim 3  wherein the step of generating the reconstructed path comprises a step of storing a length of each constituent path segment and a total length of the reconstructed path.  
   
   
       9 . The method as claimed in  claim 7  wherein the step of generating the reconstructed path comprises a step of storing a length of each constituent path segment and a total length of the reconstructed path.  
   
   
       10 . The method as claimed in  claim 1  wherein the step of generating the list comprises a step of sorting the labels into alphabetical order.  
   
   
       11 . A computer program product comprising code adapted to perform the steps of  claim 1  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       12 . The computer program product comprising code adapted to perform the steps of  claim 2  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       13 . The computer program product comprising code adapted to perform the steps of  claim 3  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       14 . The computer program product comprising code adapted to perform the steps of  claim 4  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       15 . The computer program product comprising code adapted to perform the steps of  claim 5  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       16 . The computer program product comprising code adapted to perform the steps of  claim 6  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       17 . The computer program product comprising code adapted to perform the steps of  claim 7  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       18 . The computer program product comprising code adapted to perform the steps of  claim 8  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       19 . The computer program product comprising code adapted to perform the steps of  claim 9  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       20 . The computer program product comprising code adapted to perform the steps of  claim 10  when the computer program product is loaded into memory and executed on a processor of a wireless communications device.  
   
   
       21 . A wireless communications device for enabling a user of the device to display a map on the device, the wireless device comprising: 
 an input device for enabling the user to cause the device to obtain map data for rendering the map to be displayed on a display of the device, the map data including label data for rendering labels on the map for identifying one or more map features; and    a memory for storing code to instruct a processor to: 
 generate a list of all the labels to be rendered on the map;  
 determine, for each duplicated label in the list, whether the map features associated with the duplicated labels connect on the map;  
 generate a reconstructed map feature; and  
 render on the display of the device a single instance of the label for the map feature.  
   
   
   
       22 . The wireless communications device as claimed in  claim 21  wherein the processor renders the label such that the label is aligned with a middle of the reconstructed map feature.  
   
   
       23 . The wireless communications device as claimed in  claim 21  wherein the reconstructed map feature is a reconstructed path that is reconstructed from constituent path segments derived from separate sets of map data.  
   
   
       24 . The wireless communications device as claimed in  claim 23  wherein the processor determines whether a first endpoint of a first path associated with the duplicated label matches a second endpoint of a second path also associated with the duplicated label.  
   
   
       25 . The wireless communications device as claimed in  claim 24  wherein processor renders the single instance of the label midway along the reconstructed path.  
   
   
       26 . The wireless communications device as claimed in  claim 21  wherein the processor determines a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed map feature and then reverses the direction of one or more data vectors so that all data vectors in the reconstructed map feature have a common direction.  
   
   
       27 . The wireless communications device as claimed in  claim 23  wherein the processor determines a direction of a data vector for each constituent set of map data that, when rendered, together constitutes the reconstructed path and then reverses the direction of one or more data vectors so that all data vectors corresponding to each constituent path segment in the reconstructed path have a common direction.  
   
   
       28 . The wireless communications device as claimed in  claim 23  wherein the processor causes the memory to store a length of each constituent path segment and a total length of the reconstructed path.  
   
   
       29 . The wireless communications device as claimed in  claim 27  wherein the processor causes the memory to store a length of each constituent path segment and a total length of the reconstructed path.