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<div style="direction: ltr;font-family: Tahoma;color: #000000;font-size: 10pt;">Hi All,<br>
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I'm curious about efficiency of A* vs Dijkstra in large networks. If A* tends to follow the straight line nodes until/unless it finds an obstacle, for really large networks, under what conditions is A* a better choice than Dijkstra?<br>
<br>
Also, regarding A* implementation, is it strict, or is there any way to relax the admissibility criterion as currently implemented?<br>
<br>
Finally, in using pgRouting for turn by turn, we have pre-chopped our network into short segments to ensure the nearest search node is close to the point we are searching so the directions start from a nearby point, not the nearest network intersection.<br>
<br>
For datasets as large as the one we are working with, this seems to result in a pretty high random IO tax. I wondered if anyone has some boilerplate modifying the returned route, slicing the nearest ways to the beginning and end points with ST_ClosestPoint
or similar?<br>
<br>
Thanks,<br>
Best,<br>
Steve<br>
<br>
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<p class="MsoNormal"><img src="http://sig.cmparks.net/cmp-ms-90x122.png" alt="http://sig.cmparks.net/cmp-ms-90x122.png" height="122" hspace="12" width="90" align="left">
<span style="font-size:14.0pt; font-family:"Arial","sans-serif"; color:#006C56">Stephen V. Mather<br>
</span><span style="font-size:11.0pt; font-family:"Arial","sans-serif"; color:#006C56">GIS Manager<br>
</span><span style="font-size:9.0pt; font-family:"Arial","sans-serif"; color:#006C56">(216) 635-3243 (Work)
</span><span style="font-size:11.0pt; font-family:"Calibri","sans-serif"; color:#1F497D"><a href="http://www.clemetparks.com" target="_blank"><span style=""><br>
clevelandmetroparks.com</span></a></span></p>
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