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<title>3D maps</title>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Hi Paul,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I’m not aware of any built in
procedures available in PostGIS. Something could be worked out possibly but you
would need to pull out the triangles as line segments and intersect individual
lines before interpolating a z value. This is a lot of work and I doubt that it
could be done efficiently. You would have to write the splitting and
interpolation yourself.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Perhaps you should look at one of the open
source terrain modeling tools. I’m thinking of grass.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><a href="http://grass.itc.it/">http://grass.itc.it/</a>
or <a href="http://www.jgrass.org/cgi-bin/moin.cgi">http://www.jgrass.org/cgi-bin/moin.cgi</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Here is a potential work flow:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>1. Convert your TIN to a surface<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><a
href="http://grass.itc.it/grass63/manuals/html63_user/v.surf.idw.html">http://grass.itc.it/grass63/manuals/html63_user/v.surf.idw.html</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I believe Grass is memory limited so if the
TIN is very large you may have to tile and iterate through a tile set. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>You could possibly work out something
using the pg driver <a
href="http://grass.itc.it/grass63/manuals/html63_user/grass-pg.html">http://grass.itc.it/grass63/manuals/html63_user/grass-pg.html</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>2. Use the resulting surface to process 2D
polyline into 3D polyline<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><a
href="http://grass.itc.it/grass63/manuals/html63_user/v.drape.html">http://grass.itc.it/grass63/manuals/html63_user/v.drape.html</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>You may want to densify the 2D first with <a
href="http://grass.itc.it/grass63/manuals/html63_user/v.split.html">http://grass.itc.it/grass63/manuals/html63_user/v.split.html</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Hope this is helpful<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Randy</span></font><font color=navy><span
style='color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><a href="http://cadmaps.com/gisblog/">http://cadmaps.com/gisblog/</a><a
href="http://www.cadmaps.com/gisblog.htm"></a></span></font><font color=navy><span
style='color:navy'><o:p></o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
postgis-users-bounces@postgis.refractions.net [mailto:postgis-users-bounces@postgis.refractions.net]
<b><span style='font-weight:bold'>On Behalf Of </span></b>Malm Paul<br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, November 19, 2007
7:53 AM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">PostGIS
Users Discussion</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> [postgis-users] 3D maps</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p><font size=2 face=Arial><span lang=SV style='font-size:10.0pt;font-family:
Arial'>Hi!</span></font> <br>
<font size=2 face=Arial><span lang=SV style='font-size:10.0pt;font-family:Arial'>I
have a geometry set of triangles (e.g land area), including elevations. To be
able to view e.g roads ontop those triangles I must insert points in the road
polylines with the correct elevation in each intersection (roadline - triangle
border). Att the same time I would like to insert the correct elevation of the
original points of the road-polyline. is there a command in PostGIS that could
do this for me?</span></font><o:p></o:p></p>
<p><font size=2 face=Arial><span lang=SV style='font-size:10.0pt;font-family:
Arial'>Kind regards, </span></font><span lang=SV> </span><o:p></o:p></p>
<p><font size=2 face=Arial><span lang=SV style='font-size:10.0pt;font-family:
Arial'>Paul</span></font><span lang=SV> </span><o:p></o:p></p>
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