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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hi all:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><span style='mso-spacerun:yes'> </span>With the help of
many in our lists, I finally made <span class=SpellE>pgdijkstra</span> works. Thank
you all very much.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><span style='mso-spacerun:yes'> </span>After I start to
use <span class=SpellE>pgdijkstra</span> tool, I got more questions need you
help.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>1. How shortest path are calculated? Does it optimize the
route length (use road segment length)? Or does it optimize route cost (value
of cost column)? For example, I can put value of length/speed as cost, and
optimize route on time?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>2. If I pass </span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>directed</span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> =true to <span
class=SpellE>shortest_path</span> function, which means all road segments have
directions? Can I set highways which need to be considerate direction (one-way),
and local roads have no directions (two-way) in one route? You know, in real
life, you can drive on one-way and two-way street in one trip. The route is a combination
of one-way and two-way roads.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>3. Another question about direction. Do traffic directions have
to match road segment direction? For example, a road segment start node id is
4, and end node id is 5, but traffic direction is actually from Node 5 to Node
4. Does <span class=SpellE>shortest_path</span> function support this situation?
How? Do I have to flip one-way road segments to match traffic direction?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><span style='mso-spacerun:yes'> </span>Many, many thanks
for your help.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Fay<o:p></o:p></span></font></p>
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