Hi Doug, Look up "vehicle routing problem" and the following:
http://www.sintef.no/static/am/opti/projects/top/vrp/ Here is a list of research papers available on line: http://www.sintef.no/static/am/opti/projects/top/vrp/bibliography.html Your assumption is basically correct. The solution must be searched for. In general, given a table of nodes/intersections and the distances between them, one can search all paths for the shortest path. Since this usually takes too long, one takes shortcuts (heuristics or guesses), sometimes not even attempting the best solution. (I was looking at this in about 1963 for finding the shortest length of wire to interconnect a set of electrical terminals. I have not kept up in the field.) Gordon At 01:34 PM 7/20/2008, Douglas Bateman wrote: >Sundiallists always know where they are, but do they know where they >are going? > >This rather rhetorical question is slightly off topic and directed to >our computer experts: the question is how does my satellite >navigation (Sat Nav) system in my car, or hand held, know where it is >going and how to get there when I give it an address? > >A search in Wikipedia or Google under satellite navigation talks about >the satellites, timing, position, etc, but NOT what is in my little box. > >I assume that the memory holds some form of map (vector storage, or >bit map?) and a series of nodes for every single road intersection >(and plans thereof). A route finding algorithm must exist for testing >all the nodes between and A and B. I also assume each link between >any two nodes must obey some rules about speed limits, preferences for >motorways, etc. > >Then, I assume that the incoming signal for latitude and longitude >must cause the map to 'place itself' under this lat long so that you >can see a real time display of where you are and where you are going. > >It would be nice to know more! Any advice please. > >Regards, Doug (who sometimes still get lost) >--------------------------------------------------- >https://lists.uni-koeln.de/mailman/listinfo/sundial --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
