A computer-implemented method for creating an abbreviated description of an original navigation route for sending said abbreviated description from a sending terminal to a receiving terminal via a communication network, wherein the sending terminal is a server and the receiving terminal is a client device or the sending terminal is a client device and the receiving terminal is a server, the navigation route having an originating point and a destination point, and represented by a plurality of links, each joining a plurality of nodes, each node having multiple exiting links, each exiting link having a heading, the method comprising: for each node reached by an incoming link: determining the heading of the incoming link; determining the heading of the exiting link along the route exiting the node; responsive to a determination that, of the headings of the exiting links of the node, the heading of the exiting link along the route is not the most nearly equal to the heading of the incoming link, placing a breadcrumb in the abbreviated description of the route, the breadcrumb including a representation of the coordinates of a point represented by the node a representation of the heading of the incoming link, and a representation of the heading of the exiting link along the original route; placing a breadcrumb at the beginning of the abbreviated description of the original route, the breadcrumb including coordinates representing the location of the originating point of the route and a representation of a heading of an exiting link from the breadcrumb and the breadcrumb not including a representation of a heading of an incoming link to the originating point; placing a breadcrumb at the end of the abbreviated description of the original route, the breadcrumb including coordinates representing the destination point of the route and a representation of a heading of an incoming link to the destination point and the breadcrumb not including a representation of a heading of an exiting link; the method being characterized by: determining a hint, including a bounding rectangle or ellipse between two consecutive breadcrumbs, for use in determining that an error has occurred if a link goes outside the bounding rectangle or ellipse. determining the heading of the incoming link; determining the heading of the exiting link along the route exiting the node; responsive to a determination that, of the headings of the exiting links of the node, the heading of the exiting link along the route is not the most nearly equal to the heading of the incoming link, placing a breadcrumb in the abbreviated description of the route, the breadcrumb including a representation of the coordinates of a point represented by the node a representation of the heading of the incoming link, and a representation of the heading of the exiting link along the original route; placing a breadcrumb at the beginning of the abbreviated description of the original route, the breadcrumb including coordinates representing the location of the originating point of the route and a representation of a heading of an exiting link from the breadcrumb and the breadcrumb not including a representation of a heading of an incoming link to the originating point; placing a breadcrumb at the end of the abbreviated description of the original route, the breadcrumb including coordinates representing the destination point of the route and a representation of a heading of an incoming link to the destination point and the breadcrumb not including a representation of a heading of an exiting link; the method being characterized by: determining a hint, including a bounding rectangle or ellipse between two consecutive breadcrumbs, for use in determining that an error has occurred if a link goes outside the bounding rectangle or ellipse.