Talk:Digital terrain model

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Contents 1 Proposed Merge 1.1 DTM is a subset of DEM 1.2 DTM Differs from a DEM 1.3 Changed Merge directions

[edit] Proposed Merge

A DEM is digital representation of topographic surface while a DTM is derived from a DEM. A DEM is a dataset with elevation data in digital format and that is it. A DTM refers to terrain features in digital format represented as an image, of a grid showing elevation, slope, aspect, drainage sinks, etc...DTMs are almost always a regular grid. DEMs can be a regular grid, digital contour lines, a TIN (triangulated irregular network)of a profile or series of profiles. --Ray 11:45, 28 December 2005 (UTC)

This is the first time I've seen DTM, but I've seen many occurrances of DEM. It's not my field, though. With redirects, it probably doesn't matter. Mainly I'm commenting because no one else has.Walter Siegmund (talk) 02:46, 9 February 2006 (UTC)

[edit] DTM is a subset of DEM

DEM is definitely a more broad term than DTM, and is more extensively used in the GIS field. It would be better to roll DTM into the DEM article. —This unsigned comment was added by 24.68.236.177 18:18, 24 March 2006 (talk • contribs) .

I agree with this comment. The DTM topic should be included in the DEM article and not the other way around. (SCmurky 18:11, 25 May 2006 (UTC))

[edit] DTM Differs from a DEM

I agree with the first posting. The DEM is a numerical data file. Sometimes it is rendered as an image whereby the numerical elevation values are mapped to pixel values, producing the familiar ghostlike greyscale images that only vaguely remind one of the underlying terrain. The DTM is an image derived from a graphical rendering of the DEM. The starting point is called a heightfield that is an object generated by a graphics program capable of producing shaded images, like OpenGL. The DTM is supposed to look something like the terrain from which the DEM data was obtained. —The preceding unsigned comment was added by 68.9.89.247 (talk • contribs) 15:28, 16 April 2006 (UTC)

So, this agrees with the second post too, then - DTM should be merged as a sub-topic or extension of DEM, not the other way around.—The preceding unsigned comment was added by 18.250.5.120 (talk • contribs) 23:46, 30 May 2006 (UTC)

[edit] Changed Merge directions

As I agree with the above discussion that DEM is the wider topic, I've gone ahead and changed the direction on the merge tags. Whitejay²⁵¹ 05:06, 5 June 2006 (UTC)

Good to see progress in this discussion. Walter Siegmund (talk) 05:49, 5 June 2006 (UTC)

There should be one article, covering both DEM and DTM. Viewfinder 08:56, 5 June 2006 (UTC)