Hi Rainer <div><br></div><div>I have worked with GRASS before and will check that out too. </div><div>I don't think I will manage R on my own so I will pass. </div><div><br></div><div>rgds,</div><div>Uazu<br><br><div class="gmail_quote">
On Tue, Jan 15, 2013 at 11:04 AM, Rainer M Krug <span dir="ltr"><<a href="mailto:r.m.krug@gmail.com" target="_blank">r.m.krug@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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On 15/01/13 08:24, Paul Scott wrote:<br>
> On 15/01/2013 08:53, S Coetzer wrote:<br>
>> Hi<br>
>><br>
>> If I can suggest a quick an easy way to get estimated time travel.<br>
>><br>
>> Get your x,y coordinates from point A to point B and plot it on Google maps. Use the GET<br>
>> DIRECTIONS facility, this would give you an estimated travel time and distance along with<br>
>> several possible alternative routes.<br>
>><br>
>><br>
><br>
> For a group of GI professionals, I am bitterly disappointed in these types of answers. Has<br>
> anyone heard of Djikstra's algorithm (<a href="http://en.wikipedia.org/wiki/Dijkstra%27s_algorithm" target="_blank">http://en.wikipedia.org/wiki/Dijkstra%27s_algorithm</a>) or<br>
> a* or Shooting-Star distance algorithms?<br>
> (<a href="http://www.policyalmanac.org/games/aStarTutorial.htm" target="_blank">http://www.policyalmanac.org/games/aStarTutorial.htm</a>)<br>
><br>
> From that, we can infer that distance * average speed = time right?<br>
><br>
> Come on ladies and gents! Let us foster an environment for new thinking and innovation, not a<br>
> forum for consumption of predefined OTS products.<br>
><br>
> OSGeo = Open Source = hack and pick and modify = change = new = better = share.<br>
<br>
</div></div>Well - if there are "out of the box" solutions, why not mention them so that they can be used?<br>
Easier in many regards (although not that satisfying and challenging...)<br>
<br>
But here are two ideas:<br>
<br>
1) You could use R. I wouldn't wonder if there is a package for that.<br>
<br>
2) Use GRASS:<br>
a) Rasterize your road network (NULL values for "not on road")<br>
b) use r.cost or r.walk to calculate the least cost paths along the road network (see<br>
<a href="http://casoilresource.lawr.ucdavis.edu/drupal/book/export/html/96" target="_blank">http://casoilresource.lawr.ucdavis.edu/drupal/book/export/html/96</a> "Simple Comparision of Two<br>
Least-Cost Path Approaches" for a comparison of the two)<br>
<br>
Warning: I haven't used this approach yet, these are just ideas, but they could work. To get motre<br>
info, I would suggest to google and ask on the GRASS user mailing list.<br>
<br>
Cheers,<br>
<br>
Rainer<br>
<div class="im"><br>
<br>
<br>
><br>
><br>
><br>
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<br>
</div>- --<br>
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology, UCT), Dipl. Phys.<br>
(Germany)<br>
<br>
Centre of Excellence for Invasion Biology<br>
Stellenbosch University<br>
South Africa<br>
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email: <a href="mailto:Rainer@krugs.de">Rainer@krugs.de</a><br>
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Skype: RMkrug<br>
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