1 Arc-Second DEM Data [North America]

[JOHNtheREDNECK]

So when I was playing around with some route building stuff and just messing around with it... I happened to come across 1 arc second DEM Data which appeared to work for me.

As any route builder relying on the data may know, Dovetail provides links for 3 arc second DEM data which records average height measurements over approximately 280ft increments. This 1 arc second DEM data takes the average height measurement over a distance of 90ft. So terrain looks more full and with more contrast between peaks and valleys.

I am not providing a basic tutorial for DEM Data but if you already kind of know what your doing, then you may find this helpful.

This USGS site splits the country into several "regions". The map of how the regions are broken down is also on the site.



For this to work you need to figure out the coordinates of nearly everything within your route bounds and pick the data files that correspond plus a few extra for the surrounding area.

If you are going to use this data instead of existing data you already have installed. You MUST move all existing data to a separate folder (outside the DEM Railworks folder) or delete the existing data in there.This is because of the differences in how the height was collected over distance (1 arc second vs 3 arc second) don't let the same .HGT file extension fool you!!!

This link below takes you to the parent directories of each region. Each data file is titled by its specific coordinates for the area in which it covers.
https://dds.cr.usgs.gov/srtm/version2_1/SRTM1/

[minerman146]

Thank you John for putting this up.

So terrain looks more full and with more contrast between peaks and valleys.

This is the base for great scenery!

[DanSSG]

Thank you for this DEM source.

1 arc-second is OK for the most cases. But I've hoped to use 1/3 arc-second for mountain terrain. Unfortunately the necessary tool ReDem isn't available anymore

For those who plan to extend existing routes you should know, that the terrain can vary from source by source. That happens to me on Sherman Hill where the exitsing terrain is about 4 meters lower than the new added terrain from nationalmap (which is another good DEM source)

[imnew]

Thank you

[NorthernWarrior]

Just be aware if you try and import this direct in the sim, it will crash if you are anywhere near a line of latitude. Just had this happen on a route I was playing around with and it is frustrating as heck. I can't believe after all this time they still never fixed the issue.

The only workaround is either switching to lo-res DEM at the latitude line or if you have a copy (as it's now OOP) use Redem to create the terrain for you and copy it over to the route folder.

If anyone from DTG still frequents this place perhaps they would like to explain why this annoying bug was never fixed and if there are plans to do so before the 32bit sim is regarded as end of life?

[wlenz781]

Does anyone know where to find 3 arc second DEM data. I am running into an issue where I need to import terrain on the 35ºN latitude line. Since the 1 arc second DEM data will not work without crashing, I need to find some that will.

[BoostedFridge]

Does anyone know where to find 3 arc second DEM data. I am running into an issue where I need to import terrain on the 35ºN latitude line. Since the 1 arc second DEM data will not work without crashing, I need to find some that will.

3 arc second data is next to useless in my opinion. I did a test import of the terrain for Abo Canyon, testing between 3 arc second, and two different 1 arc second sources. The 3 arc second data made the steep rocky hills of New Mexico look like the rolling hills of Kansas. There wasn't even any remote hint of cuttings, fills, or even the riverbed. The 1 arc second data was serviceable, with the USGS files being slightly more defined.

If you are stuck without ReDem, you are better off using 1 arc second, than 3.

Just be aware if you try and import this direct in the sim, it will crash if you are anywhere near a line of latitude. Just had this happen on a route I was playing around with and it is frustrating as heck. I can't believe after all this time they still never fixed the issue.

The game only crashes when you try to import the tiles ON the actual border of the line of latitude.

To get around this, I do the following:

As you are importing the terrain, keep an eye on your coordinates as you approach a line of latitude. As your tile import blocks get closer to the line, size them down so that you are not importing OVER the line of latitude. I usually size down to 1x1, and move along the line importing the blocks on the edge, going East/West.

Then go 1 tile to the north of the line, and import your terrain, leaving a 'trench' of 1 tile along the line itself.

Next I use the 'level' tool, set to an average height between the terrain elevations north and south of the trench.

Last, I will use the 'smooth' tool, with the brush size fairly large (100+), and the brush speed and falloff dialed down quite slow.

If there is a cutting or fill that the track is on/in as it crosses the line of latitude, you will obviously have to do some additional shaping.


For references sake while we are on the subject, if someone that has ReDem is building a route, but is building in an area that doesn't have better than 1 arc second DEM files available, you can merge your 1 arc second files together using QGIS (free), and import them through Redem. This is a much more painless process then having to import as you go inside the sim, and then perform the process described above at lines of latitude.