DTED Support

[SharkNose]

I couldn't find it in the manual nor anywhere on these forums, so the answer is probably "no".

But, here's the question nevertheless: Can TransDEM work with DTED (Digital Terrain Elevation Data)?

Here's an example of the folder structure:



After looking up DTED on Wikipedia I found out that level 0, which is what the DTED data that I downloaded is, has a resolution of 900 meters. That's not likely to give me other than a very (VERY) general idea of the terrain, is it?

I wanted to see what the mountains of Guatemala looked like. There are some railroads there.

Thanks.

Andrew

[geophil]

DTED0 was my first contact with a DEM in the late 1990s, in conjunction with Railroad Tycoon II, but since it's only 30 arc sec or 900 m (along the meridian) it's not to helpful for today's railway simulations. Therefore, I did not support the format in TransDEM.

SRTM 3 arc sec or ASTER GDEM 1 arc sec (nominally) will be the better choice. You may have to stitch together a number of 1 x 1 degree DEM chunks to cover the whole country. Get an overview map from one of the map tile servers first and let TransDEM indicate which SRTM files are needed.

[SharkNose]

Thanks, Roland. I did a Google search on ASTER GDEM and discovered the NASA Reverb/Echo site (which now I find is mentioned in your TransDEM manual ). I created an account and managed to figure out how to retrieve the data. TransDEM happily imported the terrain around Guatemala City and I traced a rough rail route from Google Earth. There's a huge mountainous volcano nearby that must be overwhelming to look at. It alone takes up 256 Trainz baseboards! Due to it's enormity, Trainz clips the top off at any real distance. The minimum elevation in the route is 318 meters - maximum is 3748 m.

Fun stuff!

Thanks again for your assistance.

Andrew

[geophil]

The minimum elevation in the route is 318 meters - maximum is 3748 m.

There are two functions in TransDEM that might help. One is "Adjust elevations in entire route" in the Trainz menu. You can try and lower the route so that the peaks are below 30000m. As far as I know the valid range in Trainz is -3000m to +3000m. But it may not work if the route has already been edited in Surveyor and the 3000+ peaks have been clipped off. The other function is to edit the DEM itself, either via the "Raise/lower DEM" command or with the help of a single control point with a relative adjustment.

[SharkNose]

Trainz clips the top off at any real distance.

I'm sorry, I should have elaborated. I think it's the draw distance in Trainz that does the clipping. I have it set to maximum. As I travel closer to the top of the volcano, all the terrain is there and I can even sit on top of the volcano and look down, but again the draw distance clips the terrain all around the base of the volcano.







For the curious, the volcano in the upper left of the mini map above is Volcán de Agua.