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Method for creating a directory of road sections, method for ascertaining all road sections within a search area, and computer program

  • US 9,214,097 B2
  • Filed: 02/08/2008
  • Issued: 12/15/2015
  • Est. Priority Date: 04/03/2007
  • Status: Expired due to Fees
First Claim
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1. A method for creating a directory of road sections of a digital road map portion for a navigation system, wherein the directory receives a data structure of an ordered N-tree, in which the road sections are stored in nodes, the method comprising:

  • a) assigning a geographic location to each of the road sections;

    b) assigning an orientation to each of the road sections;

    c) defining a search tree condition for the road map portion, wherein;

    (i) the road map portion is partitioned into N sublevels by a root road section, precisely one of which sublevels contains the root road section;

    (ii) the sublevels of the road map portion are situated in relation to one another as a function of respective orientations of the sublevels relative to the root road section; and

    (iii) all road sections are assigned to precisely one of the sublevels of the road map portion and thus precisely one subtree of the node;

    d) selecting one of the road sections;

    e) searching for the selected road section in the tree, wherein the search ends at a terminal node having at most N−

    1 subtrees, none of which contains the selected road section;

    f) appending the selected road section as a leaf to the terminal node according to the search tree condition;

    g) repeating steps d) through f) until each road section has been selected precisely once; and

    h) storing the directory on a data carrier.

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