Hog Textures

[steamboateng]

About a year and a half ago I started to research using Hog textures in Surveyor. The Tiger and the DEM part dulled my enthusiasm...........
Ready to try again, but before I start climbing that learning ladder I gotta know one thing........
.........once a hog texture is committed to a Surveyor map, can it be modified and saved in Surveyor.......stuff like tunnels and cuts, a tweak here and there to accomodate Trainz objects.....
Regards,

 

[geophil]

The HOG (or TransDEM) ground textures serve the sole purpose of reproducing a cartographic map image on Trainz terrain. Technically each texture is just a monochrome patch, filling the 10 x 10 m area of a Trainz ground vertex.

When creating the terrain, HOG (or TransDEM) take the cartographic map provided as input, analyse the colour value to each map pixel, find the matching texture in its texture set and assign the texture to the ground vertex. The colour value also goes to the minimap.

Later, when elaborating the route, these initial ground textures will usually be painted over by proper textures, just as you do with the default grey/orange 10 m grid texture.

To make the initial ground texturing reflect additional, user-specific features, you have to add them to the cartographic map image prior to processing it with HOG. (In TransDEM you can add vector data, which transforms to Trainz splines, at any time. Vector data can be used to mark such additional features.)

geophil

 

[backyard]

Dr. GeoPhil I presume...

8) Why do HOG textures for rail make short quick curves?

I can deal with the long logical radius curves, but sometimes in a seemingly straight tangent, a short radius curve appears.

Does it have to do with resolution(30m vs 10m)?

 

[Dermmy]

Allen, assuming the HOG lines are generated from TIGER data, then they are at best a very rough guide to where the track should be - witness the regularity with which rivers are drawn half way up hillsides rather than through the valleys.....

Andy

 

[backyard]

8) I have noticed, the "shelf" area, where it seams to me the track should be...

 

[geophil]

Ground texture resolution is an important aspect. This resolution is always 1 pixel per 10 metres, defined by the Trainz terrain model. Due to rounding effects, features right on the edge between two ground vertices may jump between the two. In some cases this may yield unexpected "tight curves".

A more specific issue is the accuracy of map and DEM source. TIGER data is specified as 1:160000, not an ideal scale. Occasionally, TIGER vectors may also add a kink or two. The only reason why people were/are using TIGER is because TIGER fits nicely with MicroDEM. No hassle with geo-referencing.

The way it should be is shown in this example of Canadian data. The map is a scanned 1:50000 CanMatrix image, the DEM a terrestrial Canadian 0.75 arc sec. The location is Kicking Horse Pass, Canadian Pacific Railroad with the two spiral tunnels, west of Lake Louise.



Rendered with TransDEM the example shows two types of contour lines, those of the printed map and those generated by TransDEM, derived from DEM heights. Apart from a few local details overall matching is quite good. It should be this way for optimum results in Trainz. (Unfortunately, with other sheets of the same map series deviations are more noticeable and you may end up with a highway or a railroad in the river.)

geophil

 

[steamboateng]

OK geophil, what your saying is that I can't change terrain features in Trainz Surveyor, (cut down a hill, or make a plateau out of one, or make a cut thru a ridge, etc.) I'm stuck with the terrain that Surveyor gives me after being processed via HOG program: ie the underlaying map data that Hog processed won't allow me to make changes. Changes must be made to the map data itself.
If that's the way it is, then I can see that problems can arise when trying to put Trainz assets in particular locations. Running tracks on grade, laying juctions and switching yards on grade, etc. could be a tedious procedure.
However, all the time saved in creating terrain would more than make up for the hassle.
I got my learning ladder ready so I think Ill give it a shot.
Thanks for the info.
Regards........

 

[geophil]

Slight misunderstanding.

You have the full freedom of modifying both terrain height and ground textures after the terrain generation tool has accomplished its job.

HOG, MapMaker or TransDEM generate the Trainz terrain based on DEM data. Additionally, HOG and TransDEM can paint the ground with a texture which normally reflects a cartographic map, provided as a separate input. You will need such a map to find your way around. Often though, particularly with TIGER, the map leaves something to desire for details. For the ground textures, HOG uses the HOG texture set and TransDEM uses the TransDEM texture set.

After tool-based terrain generation is completed, you go to work in Surveyor just as you would do when building on a conventional, flat baseboard at sea-level.

What I understood from your initial post was that you wanted to mark some features which may not be shown on the cartographic map, like tunnel portals, bridges etc. and find them back in the ground textures. And that's difficult to achieve.

geophil

 

[steamboateng]

Sorry if I wasn't clear on what my concern is. I know that the Dem works in 10 meter increments, and Tiger mapping of ground details is rough.
I was concerned with actually modifying the map in Surveyor to accomodate Trainz assets. I have a specific project in mind which motivated my query.
Part of the terrain features of a particular map will include a shallow tunnel, perhaps 8 to 10m below 0 map level (Surveyor) into a rise, perhaps 5 m above, upon which a city downtown area resides. The tunnel is about 200m long, emerging from the north side of town. Allowing the Dem some innacuracies, I was concerned if it would pick up the gentle grade down into and out of the tunnel. Also, knowing that most Trainz tunnel assets are stuck to a line on the map grid, I would have to deviate somewhat from the actual track map. I have to fit a two track main into the tunnel cuts. Knowing I can modify the terrain detail as in any normal map, assures that I can fit track and tunnel into available space.
You seem to know quite a bit about this stuff, so I"ll almost assuredly be knocking on your cyberspace door in the future.
Thanks again for your patience and help.
Regards..........
PS: To the uninitiated Googlers out there, I found only two sites under "Hog terrain". However, I did find out a lot about where hogs live, what they eat, what gun to shoot 'em with, and how their futures are doing on the NYSE!

 

[geophil]

For best results I recommend high resolution NED DEMs as provided by USGS Seamless Server: http://seamless.usgs.gov/website/Seamless/

For many parts of the USA you will find 1/3 arc sec data which translates to 10m spacing. 10 m DEMs often resolve detailed features like railroad cuttings or high fills. As long as your route is reasonably short the amount of data should be manageable. Download in GeoTIFF format, to achieve maximum vertical resolution. The default format would give elevations rounded to integral metres.

geophil