DEM Route Track Question

[dbgallant77]

I created a route of my local area, Marietta GA, using TranzDEM and it turned out great. The track placements are extremely accurate and the topography (hills, slopes, grades) are just what I expected them to be.

My problem though, is that in many places, the track (fixed height spline track, the one with the yellow spline point circles) does not "conform" to the terrain when I used the "Set Spline Height" tool. The terrain actually covers up the track and just the very tops of the rails are showing.

If I change the spline points to "non-fixed height" by using the "Remove Gradient" tool, then it does the same thing, only the tops of the rails are showing.

What am I doing wrong....how can I fix this?

 

[JackDownUnder]

Have you checked the DEM height, it can be lowered

 

[dbgallant77]

JackDownUnder, I have never done that before.....how do you check and lower the DEM height?

 

[dbgallant77]

Sorry to be asking again, but how do you check and lower the DEM height?

 

[pitkin]

My experience with TransDem is for an older version, so this may not be relevant. However, I suggest you delete the track if it was laid down with Transdem, and lay it again manually.

Or, use TransDem again but use a different track (I assume one without fixed spline heights).

 

[redbaran11]

If you are using the transdem ground textures, simply paint over them with any other texture. This should "unhide" them

 

[dbgallant77]

Thank you everyone for your comments and suggestions - I will try them out.

 

[Forester1]

Have you tried "smooth spline"? It might help, but not sure.

 

[JCitron]

I average out the spline grade and surface. I take height points using Google Earth application, not the maps.google.com and use that to find them on the route in Trainz. The difference is probably a few meters at the most in some places, so the terrain is close but the problem we have is we have to deal with steps and can't get the smoother transitions in heights. Instead of going up and down and worrying about the height differences, I smooth the spline over the difference between the various points and be done with it. It's close enough and works fine.

While doing this, I do occasionally encounter those places where no matter what I do, I can't get the terrain to smooth out properly. It's those locations that require a bit of engineering work and employ splines and walls if needed. It may not always be what's in the real location, but because of our lower digital resolution compared to the analog real world, there's no other alternative unless I want floating splines which I absolutely despise. These locations are due to close proximity of such things as bridges or other tracks that in real life wouldn't present a problem, but because we have steps end up making a mess. These locations also occur due to the DEM resolution not being high enough to pick up height differences and is sometimes due to errors in the satellite imagery. I've run into this in my own hometown due to a high rail grade placed next to a hill on one side and lower factories on the other. Everything from the hill, grade, and factories becomes one blob on the DEM.

There's another thing to mention here. I never bother to place the track in TransDEM or let the program trace the route for me with a traced off route on the map. The reason is there are details that get covered over such as sidings and trackside details. I use the track markings as provided by the topographic map and in addition this allows me to add in branches that were once abandoned because I can see their locations clearly and lay me track myself which I do by looking down upon the route traced out on the map. I noticed that curves come out particularly well using this method and once my track is in place, I go back afterwards and make the adjustments and correct the heights.

 

[dbgallant77]

Thank you JCitron for your detailed advice, I will use what I can.

I was very pleased and surprised by the details of the mainline track and sidings that I got from the TransDEM process that I used, except for, of course, the "floating splines"...! I'm slowly going over the worst areas and raising/lowering/adding spline points to make everything look "presentable". Then I use the Topology - Height up tool if possible, and then I'll "fill-in" with walls/dirt/rock/bushes, etc. But the "Smooth Spline" tool does not help at all....I've tried that to no avail.

Thanks again everyone....!

 

[JCitron]

...But the "Smooth Spline" tool does not help at all. ...I've tried that to no avail.

What is the resolution of your DEM?

If your DEM file is lower than 1/3-arc second resolution, you'll have trouble with lack of details, and using a 10-meter grid only makes things worse because then you'll end up with the either-or issue with there's either a lump, or a hole.

You may want to investigate using the 5-meter grid in Trainz, but don't upgrade your baseboards. You need to export your data like that from TransDEM, otherwise you'll end up with broken textures. If I'm remembering correctly, there's an option in TransDEM to specify how many baseboards you want at 5-meter, so you can do this closest to the tracks with the less detail further out. The thing is sometimes no matter how high the resolution you're still going need some extra help with splines and other means to fill in the voids because we live in a stepped digital world in Trainz and not the natural infinite analog world where smoothing tools have an infinite resolution.

 

[dbgallant77]

Sorry John for the delayed response.....thank you for your input! I cannot remember all the exact steps I took, resolutions and grids I used (I think it was 5-meter grids) but here is an older tutorial I used for most of my work.....[h=1]TransDEM Tutorial - Basic Trainz Route from Scratch ... https://youtube.com/watch?v=Meeq_5_keYs[/h]

 

[JCitron]

Sorry John for the delayed response.....thank you for your input! I cannot remember all the exact steps I took, resolutions and grids I used (I think it was 5-meter grids) but here is an older tutorial I used for most of my work.....TransDEM Tutorial - Basic Trainz Route from Scratch ... https://youtube.com/watch?v=Meeq_5_keYs

No worries on getting back.

That tutorial is similar to the one I put together in paper. The issue I have with the National Geologic side of things is once we've got a set method, they fiddle with that end making our documentation obsolete.

The 5 meter grid is best for image resolution and terrain modification but you also need the 1/3 arc-second or 1/9 arc-second data. These have the finer details needed overall making for a much better terrain. It still doesn't get around the fact that we're using digital data on an analog world and you'll run into places where the ground will do what it wants to do no matter how much we want to do something else. In those locations we have to resort to fills, splines and bushes to hide the edges.

 

[dbgallant77]

Thanks again John.....got my work "cut out" for me! The route is approximately 35 miles total, and after "cruising" around it, 99.9% of it shows only the tops of the rails.....!

 

[JCitron]

Thanks again John.....got my work "cut out" for me! The route is approximately 35 miles total, and after "cruising" around it, 99.9% of it shows only the tops of the rails.....!

That's mean!

There's a longish solution but it beats relaying track. Take another cruise and remove the fixed height from the tracks which is found under the advanced pull-out in Classic Surveyor. The tool is located in the lower corner next to where you adjust the height. When you do that, the track spline points will turn white and sit on top of the terrain. At this point you can now smooth and adjust the track much more easily (hopes) and follow the grades more accurately. There's going to be places, though that are going to need fills, embankments, and walls but it won't be as bad as you see right now.