I’m fairly new to TransDEM and GIS, and I'm struggling with my project. I’m hoping someone can help identify where I’m going wrong. I’ve been working through the TransDEM Trainz Edition tutorial and have run into two problems when creating a route for Trainz Railroad Simulator 2022.
Software
- TransDEM 2.6.7 (64-bit)
- Trainz Railroad Simulator 2022, Steam edition
- Trainz build 137673
- Windows 11
I am trying to create part of the Waterloo Subdivision in Ontario, Canada.
My terrain source is LiDAR-derived DTM data from the Ontario Ministry of Natural Resources. The working terrain is in UTM Zone 17N. I also have 2024 Region of Waterloo aerial imagery (10 cm resolution) and railway vectors.
The DEM, aerial imagery and railway vectors appear to align correctly in TransDEM.
Problem 1 – terrain/baseboards
I exported the terrain using Trainz → Export & Create → DEM & Ground Textures.
The export settings included:
UTM zone: 17T
Extent: E541760–557600 / N4800960–4809600
Baseboard grid offset: x=0, y=0
5 m grid: All
Smoothing: 0.00
Route Filter: Apply, Radius 0
Ground Texture from Raster Map: off
Trainz version: T
TransDEM reported:
22 × 12 possible baseboards (264)
46 baseboards actually created after filtering all 46 in 5 m grid
The generated route imports into TRS22 through Content Manager with 0 errors and 0 warnings, and the LiDAR terrain relief is visible in Surveyor. However, there are some very large vertical fissures/cliffs between adjoining baseboards. The terrain on the two sides does not meet at the same elevation.
I also noticed this in the TransDEM information file:
Actual Elevation Range Minimum = -2147483648 m
Actual Elevation Range Maximum = 356 m
Is the -2147483648 m minimum an indication that my DEM contains NoData values that TransDEM is treating as elevations? Could that be responsible for the severe discontinuities between baseboards?
Problem 2 – UTM aerial-image tiles
Following the UTM overlay portion of the tutorial, I used:
UTM fixed grid: 1000 m
UTM selection: E542000–557000 / N4801000–4810000
1000 m UTM tiles
2D
Slightly underground
Maximum texture size: 4096 px
Route Filter: Apply, Radius 0
UTM03 template
Layer: TransDEM-UTM
TransDEM then reports messages such as:
Baseboard for UTM tile not found: 542000 4808000. Skipped.
and similar messages for numerous other UTM coordinates.
I initially exported directly to the TransDEM-created route folder.
As another test, I imported the route into Trainz, confirmed that the terrain appeared in Surveyor, opened the route for editing in Content Manager, and then selected the Trainz working copy shown by TransDEM as:
kuid2 276004 20011 1 Waterloo Sub
When I repeated the UTM export to that version, I received a mixture of messages:
Baseboard for UTM tile not found: ... Skipped.
and
UTM tile already exists: ... Skipped.
The route's mapfile.obs was modified by the operation and Trainz accepted the submitted edits without errors, but I cannot see any aerial-image UTM overlays in Surveyor.
One thing I am unsure about is the Route Filter Radius. I used Radius 0 when creating the terrain because I wanted only baseboards touched by the railway. Is that incorrect when the route will subsequently use 1000 m UTM overlay tiles? Should the terrain initially be generated with additional baseboards around the railway (for example Radius 2 or 3) so that TransDEM has baseboards available for the UTM tile anchor positions?
I would appreciate advice on both issues:
What is causing the extreme terrain discontinuities between some adjoining baseboards, and is the -2147483648 m elevation significant?
What is the correct terrain/baseboard and Route Filter setup for automatic placement of 1000 m UTM tiles in TRS22?
I’m happy to provide screenshots, the TransDEM info file, or GDAL information for the source DEM if that would help.
Thanks for any guidance. I’m still learning TransDEM, so please let me know if I have misunderstood any part of the workflow.