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    <p>First of all "being on the wrong course" can be easily detected : the length of the shortest path to the destination is increasing. Or if you have some "checkpoints" along your optimal path then the user is going away from the next checkpoint.</p> <p>For the complexity don't use a point every 5mts or other distance : you need to have some main points in your map (each door, hallway crossing...) you can give you general direction. You can even imagine prec-omputing shortest path between each building and then inside each building ; your first need to leave the building to go to the other one. </p> <p>Anyway once you have these main points you only need to add one point to you map (the user position) and connect it to the neighboring "main points".</p> <p>How many nodes do you have in your graph for now ? </p> <p><hr> <strong>EDIT :</strong></p> <p>Basically the idea is the following one : given all the roads it is really easy to pre-compute the shortest path from any point of the road to any building. No need to do that for every road, only consider every intersection or building as a node in your graph. Then given a point on the road yon only have two possibilities to read a node : left or right. (This suppose of course that people stay of the road but can be easily adapted ;) ). </p> <p>Now given a person position find the closest road and find the shortest path to these roads. You now have a few positions on different roads and it's easy to compute the shortest path to the destination. Since almost everything is pre-computing you an update your info multiple times per second.</p> <p>You can give instruction to the person and if you notice that the distance to destination is increasing you can warn him he is going in the wrong direction.</p>
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    1. USLoïc Février
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    1. COok first of all thanks a lot for your reply i was losing hope! Right now around 15 nodes for all the buildings(only for the entrances and they are going to be my main points as you mention) and the roads im yet to do it because i have not yet decided on the separation between 2 points. Could you please elaborate on the precomputing part? Doesn't the checkpoints mechanism require me to store coordinates of very short distances?
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    2. COWith only so few points wouldn't it be easier to show the user a map of the college and on top of that the road to follow ? How many nodes in each building ? (10, 100, 1000 ?)
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      1. USLoïc Février
    3. COok just showing the path was my last semester project,this year audible directions. Each building has only 1 point(entrance,door etc). We decided to help the user only navigate to his block.
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