[Freegis-list] TIN Simplification

[Chris Ryan]

Thanks Ronan,

 

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.


 

Does anyone have any ideas? Or alternatively, any thoughts on the
adequacy of a TIN >> Raster Grid >> TIN method of reducing TIN size?

 

Thanks for your time,

 

Chris Ryan

 

-----Original Message-----
From: Ronan GOLHEN [mailto:ronan at informatique-mer.fr] 
Sent: Friday, 13 February 2004 3:41 AM
To: cjr03 at uow.edu.au
Subject: RE : [Freegis-list] TIN Simplification

 

If your TIN is a grid, I do such thing using GMT (General Mapping
Tools). 

 

 

Ronan GOLHEN

Technical Manager

I&M  <http://www.maxsea.com> http://www.maxsea.com
<http://www.navcenter.com> http://www.navcenter.com 

mailto:ronan at informatique-mer.fr

Tel:33 (0)5 59 43 81 02     Fax: 33 (0)5 59 43 81 01

Mobile : 33 (0)6 88 35 02 57

 

-----Message d'origine-----
De : Chris Ryan [mailto:cryan at ccwf.cc.utexas.edu] 
Envoyé : jeudi 12 février 2004 21:19
À : freegis-list at intevation.de
Objet : [Freegis-list] TIN Simplification

 

Hi,

 

Does anyone know of free software that can reduce the complexity of a
TIN terrain model to within a prescribed accuracy or file size?

 

Regards,

 

Chris Ryan

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