http://www.model-this.com/archives/11 Model What!? Model-This! Sun, 07 Feb 2010 15:49:00 +0000 hourly 1 http://wordpress.org/?v=3.0 http://www.model-this.com/archives/11/comment-page-1#comment-301 Dave Sun, 07 Feb 2010 15:49:00 +0000 http://www.model-this.com/?p=11#comment-301 I appreciate your clarifications and you will get no argument from me. The brief articles hosted here were meant to give someone unfimilar with machine control a “knocking around knowledge” and being so I took some liberties with certain explinations. I appreciate your clarifications and you will get no argument from me. The brief articles hosted here were meant to give someone unfimilar with machine control a “knocking around knowledge” and being so I took some liberties with certain explinations.

]]> http://www.model-this.com/archives/11/comment-page-1#comment-300 Ian Lilly Sun, 07 Feb 2010 06:18:08 +0000 http://www.model-this.com/?p=11#comment-300 I'd clarify your definitions a little more. My understanding is that a DTM is typically made up of data that represents a terrain surface. It might be gridded data (eg least squares, min curvature, etc or simply closely spaced observed data - eg LIDAR or laser ranging). A DTM can also be a TIN but a it's not necessary. A TIN is a triangulated surface but has special characteristics. It has "break lines" which are typically breaks in slope which triangles DO NOT CROSS. Examples are ridge lines, streams, curbs, geological fault lines, escarpments etc. Typical programs to generate DTM are gridding programs or triangulation programs (eg TRIANGLE or ACORD by Schewchuk or Watson resp) and are a Delaunay triangulation. TINs are typically NOT Delaunay. I’d clarify your definitions a little more.
My understanding is that a DTM is typically made up of data that represents a terrain surface. It might be gridded data (eg least squares, min curvature, etc or simply closely spaced observed data – eg LIDAR or laser ranging). A DTM can also be a TIN but a it’s not necessary.
A TIN is a triangulated surface but has special characteristics. It has “break lines” which are typically breaks in slope which triangles DO NOT CROSS. Examples are ridge lines, streams, curbs, geological fault lines, escarpments etc.
Typical programs to generate DTM are gridding programs or triangulation programs (eg TRIANGLE or ACORD by Schewchuk or Watson resp) and are a Delaunay triangulation. TINs are typically NOT Delaunay.

]]>