DEM maps with flat baseboard issues

joshmeister

Proud Railfurz Member
I'm getting back into using TransDEM to work on a few things and am getting my DEM maps from this website https://viewer.nationalmap.gov/basic/ which offers great and easy ways to DL files I need to convert in TransDEM. One issue I am finding though in TransDEM is that due to the curvature of the Earth, when I DL parts of a map that will need to be merged together in TANE, I keep finding that my merger points are all just flat baseboards with no features on them (Like in the below images) and I am not really sure or proficient enough with TransDEM to know how to fix this "Cut off". Anyone that uses the program alot have any tips/suggestions on how I can fix this issue?

fki77vz.png



zcmvLL0.jpg
 
I'm getting back into using TransDEM to work on a few things and am getting my DEM maps from this website https://viewer.nationalmap.gov/basic/ which offers great and easy ways to DL files I need to convert in TransDEM. One issue I am finding though in TransDEM is that due to the curvature of the Earth, when I DL parts of a map that will need to be merged together in TANE, I keep finding that my merger points are all just flat baseboards with no features on them (Like in the below images) and I am not really sure or proficient enough with TransDEM to know how to fix this "Cut off". Anyone that uses the program alot have any tips/suggestions on how I can fix this issue?

Hmmm, I personally have generated a number of TransDEM routes, and can honestly say I have never seen this phenomenon. People more expert than myself might answer you after I do, but my assumption would be a shortcoming in the original DEM data. It might be worth trying raw data from a different source to see if it continues to occur?
 
I think this is caused by the DEM file being smaller than the selected area, causing those places to fall off to zero.

If you are planning on merging another DEM into the current route, you might want to trim back a row or two t build in a bit of overlap at the merge point.
 
I think this is caused by the DEM file being smaller than the selected area, causing those places to fall off to zero.

If you are planning on merging another DEM into the current route, you might want to trim back a row or two t build in a bit of overlap at the merge point.

Can you shoot me a PM John? Everytime you pop up your advise in PM's seems to help me fix my issues LOL.
 
If you have the route file open when you do the DEM Export.....that problem will disappear and will also trim of excess baseboards and DEM map.
 
If you have the route file open when you do the DEM Export.....that problem will disappear and will also trim of excess baseboards and DEM map.


Actually, what I'm trying to do is extend the terrain out where the black area's are instead of deleting those flat baseboards. In TransDEM I tried using the "Fill missing DEM points feature which did add some terrain to the flat baseboards, but when I mearged the two parts of the route together, theres a 100m height difference that doesnt look right. The route I'm (trying) to do is actually Tennessee Pass if that helps. on the image below, if you look at the 2nd purple box from the bottom on the right hand side, thats where the DEM is dropping off to a flat baseboard in the black and thats the area I'm trying to add the terrain to so that part will merge nicely and evenly together with the left hand side of the next map.

fki77vz.png
[/IMG]
 
Last edited:
Download the adjoining DEM to that side would fix that problem

Thats what I did, but when I merge them together in Trainz theres the 100 plus meter height difference I was talking about...

Look at the pic of the DEM on TransDEM again that I posted, the hog lines for the track go off onto the black part on the right side, the black part means that it's just a flat baseboard with no terrain, thats what I'm trying to fix, I need that to have terrain so when I merge both routes in Trains that section isnt on flat baseboards and idk how to make it have the terrain thats being cut off in TransDEM.
 
Last edited:
This is a screen grab of the left side of the next DEM map I need to merge with the one at the start of the post. TransDem is making the terrain file crooked and it's cutting off the edges where I need to merge the maps together in trainz so that they are flat baseboards, thats what I'm wanting to fix and idk how to do that, I'm for from being any kind of pro with TransDem. Btw this is the website I am using to dl the DEM's to get them into TransDEM, dont know if this helps or not. https://viewer.nationalmap.gov/basic/

I2zdrrl.png
[/IMG]
 
Last edited:
The black part of that image will always be flat (as in default Trainz baseboard height/look), as there are no DEM info there for TransDEM to work with.
 
Back
Top