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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'>Thanks Ronan,</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The problem is that it’s not a grid.
I have a 500 MB triangular network (TIN) representing a terrain surface than I
am trying to intersect with a water surface TIN in order to generate a flood depth
surface (also a TIN). Currently the process takes 12 hours. I’m looking
for a way to reduce the size (and hence processing time) of the terrain TIN by
removing the points and triangles that will have the least impact on the accuracy
of the model. The only way I can think to do this at the moment is by
converting the TIN to a grid and then back to a TIN with a set maximum number
of TIN points. However, I think this is a bad way to do it and will produce a
relatively poor approximation of the original TIN. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Does anyone have any ideas? Or alternatively,
any thoughts on the adequacy of a TIN >> Raster Grid >> TIN method
of reducing TIN size?</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thanks for your time,</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Chris Ryan</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 face=Tahoma><span
lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>-----Original
Message-----<br>
<b><span style='font-weight:bold'>From:</span></b> Ronan GOLHEN
[mailto:ronan@informatique-mer.fr] <br>
<b><span style='font-weight:bold'>Sent:</span></b> </span></font><font size=2 face=Tahoma><span lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>Friday,
13 February 2004</span></font><font size=2 face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma'> </span></font><font
size=2 face=Tahoma><span lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>3:41
AM</span></font><font size=2 face=Tahoma><span lang=EN-US style='font-size:
10.0pt;font-family:Tahoma'><br>
<b><span style='font-weight:bold'>To:</span></b> cjr03@uow.edu.au<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE : [Freegis-list] TIN
Simplification</span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 color=navy
face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial;
color:navy'>If your TIN is a grid, I do such thing using GMT (General Mapping
Tools). </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 color=navy
face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font></p>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 color=navy
face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font></p>
<div>
<p class=MsoAutoSig style='margin-left:35.4pt'><font size=1 color=navy
face="Times New Roman"><span lang=EN-GB style='font-size:9.0pt;color:navy'>Ronan
GOLHEN</span></font></p>
<p class=MsoAutoSig style='margin-left:35.4pt'><font size=1 color=navy
face="Times New Roman"><span lang=EN-GB style='font-size:9.0pt;color:navy'>Technical
Manager</span></font></p>
<p class=MsoAutoSig style='margin-left:35.4pt'><font size=1 color=navy
face="Times New Roman"><span lang=EN-GB style='font-size:8.0pt;color:navy'>I&M
</span></font><font size=1 color=navy><span lang=FR style='font-size:8.0pt;
color:navy'><a href="http://www.maxsea.com"><span lang=EN-GB>http://www.maxsea.com</span></a></span></font><font
size=1 color=navy><span lang=EN-GB style='font-size:8.0pt;color:navy'>
</span></font><font size=1 color=navy><span lang=FR style='font-size:8.0pt;
color:navy'><a href="http://www.navcenter.com"><span lang=EN-GB>http://www.navcenter.com</span></a></span></font><font
size=1 color=navy><span lang=FR style='font-size:8.0pt;color:navy'> </span></font></p>
<p class=MsoAutoSig style='margin-left:35.4pt'><font size=1 color=navy
face="Times New Roman"><span lang=FR style='font-size:8.0pt;color:navy'><a
href="mailto:ronan@informatique-mer.fr">mailto:ronan@informatique-mer.fr</a></span></font></p>
<p class=MsoAutoSig style='margin-left:35.4pt'><font size=1 color=navy
face="Times New Roman"><span lang=FR style='font-size:8.0pt;color:navy'>Tel:33
(0)5 59 43 81 02 Fax: 33 (0)5 59 43 81 01</span></font></p>
<p class=MsoAutoSig style='margin-left:35.4pt'><font size=1 color=navy
face="Times New Roman"><span lang=FR style='font-size:8.0pt;color:navy'>Mobile
: 33 (0)6 88 35 02 57</span></font></p>
</div>
<p class=MsoNormal style='margin-left:35.4pt'><font size=2 color=navy
face=Arial><span lang=FR style='font-size:10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Tahoma><span
lang=FR style='font-size:10.0pt;font-family:Tahoma'>-----Message d'origine-----<br>
<b><span style='font-weight:bold'>De :</span></b> Chris Ryan
[mailto:cryan@ccwf.cc.utexas.edu] <br>
<b><span style='font-weight:bold'>Envoyé :</span></b> jeudi 12 février
2004 21:19<br>
<b><span style='font-weight:bold'>À :</span></b>
freegis-list@intevation.de<br>
<b><span style='font-weight:bold'>Objet :</span></b> [Freegis-list] TIN
Simplification</span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=3
face="Times New Roman"><span lang=FR style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'>Hi,</span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'>Does anyone know of free
software that can reduce the complexity of a TIN terrain model to within a
prescribed accuracy or file size?</span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'>Regards,</span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='margin-left:70.8pt'><font size=2 face=Arial><span
lang=EN-US style='font-size:10.0pt;font-family:Arial'>Chris Ryan</span></font></p>
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