System and method for synchronizing map images

Abstract

An originally non-georeferenced raster map, which may have resulted from scanning and storing a non-georeferenced paper map, is georeferenced with reference to a georeferenced map, such as a vector map. Points denoting common features, such as road intersections, on each map are captured as point-pairs. When two point-pairs have been captured, a computer system calculates two functions, one converting the x,y coordinates of the raster map to the lat,lon coordinates of the vector map, the other converting lat,lon to x,y. Thereafter, the maps may be viewed simultaneously—top-and-bottom, side-by-side—or quasi-simultaneously, for example, toggling rapidly back and forth. The georeferencing functions are used by the system to effect manipulation of one map as the other map is manipulated. Thus, any manipulation of the vector map—scrolling, zooming, etc,—by a user is mimicked by the raster map.

What is claimed is:  
     
         1 . A computer-implemented method of manipulating map images, each of which has a natural, internal coordinate system and is georeferenced by a georeferencing function, relative to geographic coordinates, comprising: 
 (a) simultaneously displaying each map image in its respective internal coordinate system    (b) altering a first of the map images;    (c) determining the geographic coordinates of the alteration to the first map image by applying thereto its georeferencing function if the alteration's coordinates are not already in geographic format; and    (d) altering the other map images so that their displays contain the same alteration as the first map image at the same geographic coordinates as the first map image's alteration by applying to the other map images their respective georeferencing function if they are not already in geographic format.    
     
     
         2 . The method of  claim 1 , wherein: 
 the altered first map image display and the altered other map image displays cover the same geographic area.    
     
     
         3 . The method of  claim 1 , wherein: 
 the altered first map image display and one or more of the other map image displays cover some but not all of the same geographic area, and    step (c) is effected by determining the geographic coordinates of as much of the alteration of the first map image as can be included on each of the one or more other map images.    
     
     
         4 . A method as in  claim 1 , wherein: 
 the alteration of the first map image comprises moving the first map image, and    the alteration of the other map images comprises movement thereof in the same sense and amount as the movement of the first map image.    
     
     
         5 . A method as in  claim 4 , wherein: 
 the movement is panning, scrolling up or down, scrolling left or right, scrolling diagonally, rotating, zooming in or zooming out.    
     
     
         6 . A method as in  claim 1 , wherein: 
 the alteration of the first map image comprises adding or deleting an artifact to or from the first map image.    
     
     
         7 . A method as in  claim 6 , wherein: 
 the artifact is an alphanumeric legend, a symbol, a line or a polygon.    
     
     
         8 . A computer system for manipulating map images, each of which has a natural, internal coordinate system and is georeferenced by a georeferencing function relative to geographic coordinates, comprising: 
 (a) monitor facilities for simultaneously displaying each map image in its respective internal coordinate system;    (b) mouse/keyboard facilities for altering a first of the map images;    (c) first facilities for determining the geographic coordinates of the alteration to the first map image by applying thereto its georeferencing function if the alteration's coordinates are not already in geographic format; and    (d) second facilities for altering the other map images so that their displays contain the same alteration as the first map image at the same geographic coordinates as the first map image's alteration by applying to the other map images their respective georeferencing function if they are not already in geographic format.    
     
     
         9 . The system of  claim 8 , wherein: 
 the altered first map image display and the altered other map image displays cover the same geographic area.    
     
     
         10 . The system of  claim 8 , wherein: 
 the altered first map image display and one or more of the other map image displays cover some but not all of the same geographic area, and    the first facilities determine the geographic coordinates of as much of the alteration of the first map image as can be included on each of the one or more other map images.    
     
     
         11 . A system as in  claim 8 , wherein: 
 the alteration of the first map image comprises moving the first map image, and    the alteration of the other map images comprises movement thereof in the same sense and amount as the movement of the first map image.    
     
     
         12 . A system as in  claim 11 , wherein: 
 the movement is panning, scrolling up or down, scrolling left or right, scrolling diagonally, rotating, zooming in or zooming out.    
     
     
         13 . A system as in  claim 8 , wherein: 
 the alteration of the first map image comprises adding or deleting an artifact to or from the first map image.    
     
     
         14 . A system as in  claim 13 , wherein: 
 the artifact is an alphanumeric legend, a symbol, a line or a polygon.    
     
     
         15 . An item of commerce, comprising: 
 a memory medium containing computer instructions for effecting the method of  claim 1 .    
     
     
         16 . An item of commerce as in  claim 15 , which further comprises: 
 the map images stored on the medium.