I know I have to apply the Dijkstra algorithm 
(http://en.giswiki.net/wiki/Dijkstra's_algorithm), but what I don´t know is how 
to pass just a layer as map (the layer of roads) and not the whole map, how to 
pass the point of origin and point of destiny to calculate the shortest path, 
how to calculate the sum of length of shortest path, how to select the 
different sections of the shortest path ... in ultimately, I do not know how to 
implement this operation. It is possible that this operation someone has 
already done, so that, can someone pass me the code so I can adapt it to mine? 
Also, I saw this post and I don´t know if it already has answer 
http://n2.nabble.com/Dijkstra's-algorithm-td1818808.html, if the person who 
created the post was able to use these dll's http://pgrouting.postlbs.org. 
Thank you very much.
 


Date: Sun, 1 Mar 2009 09:56:54 -0500
Subject: Re: [mapguide-users] Make a new operation: "calculate minimum path"
From: rnorthc...@gmail.com
To: mapguide-users@lists.osgeo.org


Sounds like more of a Math problem. Which amazingly, computers can do math 
better than anything else.
 
Take a look here:
http://www.springerlink.com/content/ux62418642458410/fulltext.pdf
 
the resources in the back, and the theory is what you'll have to take from it 
to build your own shortest distance routes against your datasets.
 
But you're going to probably be doing a lot of looping, and array 
loading/sorting. Finding any intersections, then at the end, you'll be building 
different routes, and if any valid route grows longer than your current route, 
you end the loop, and go build a new route until you'r out of route choices.
 
That's my 2 cents into how I'd tackle it, but there is probably more 
sophisticated mathematical algorithms you need to look into.
 
-north


On Sat, Feb 28, 2009 at 3:29 PM, Sergio Nistal Calvo <serginis...@hotmail.com> 
wrote:


Hello, 
 
I have a layer in a map that is about communication roads and I would like to 
make a operation which is to calculate the minimum path. I do not know how make 
it, any help is appreciated. I uses apache and php.
 
Thanks.



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