Using TransDEM to modify DEM data? (altering/removing manmade geography)

[Blutorse4792]

I am utilizing TransDEM to generate the terrain for a historical Trainz route. So far, I have had no issue with collecting/importing the data and generating the route file, but I've run into a problem with the DEM itself:

As you can see when contrasting the DEM against the topographic map, the former contains a number of manmade structures (in this example, a depressed highway) which did not exist during the time period I am attempting to depict. This is potentially a deal breaker for the entire project, as there are many instances in which elevated/depressed highways now occupy what were once grade-level railroad rights-of-way.

While I could, in theory, attempt to rectify this issue with the terrain tools in Surveyor (a daunting task) I am wondering if TransDEM itself offers functionality/tools that could assist in some way? While I have been using the application for many years, I have never ventured outside of its basic route generating functionality, and I wouldn't quite know where to start.

(Some of you may recall that I posted about this issue close to a year ago or so, but I've decided to revisit this challenge from a more constructive angle)

 

[JCitron]

I'm not sure if it's possible but there is the ability to manipulate data points within TransDEM to allow for stitching data and removing data points.

I'm curious because I've run into the same situation with a historic map placed on DEM data. A hill was carved out in modern times by a sand and gravel operation leaving a nasty scar in the side of an otherwise beautiful domed drumlin. The scar looks as if a monster took a bite out of the hill.

The route is difficult enough due to the real rail line being obliterated in the 1920s by two dams. The second dam is the one that did the rail line in because the company by then decided it wasn't worth it to rebuild yet again. I was able to use a 1940s topographic map that still showed the old rail line in parts allowing me to interpolate and rebuild the terrain to a certain extent.

 

[BlackDiamond1964]

Sometime you can only take your time and remove the modern highways by hand in surveyor. I needed to do this on the Laurel Line Route. I had to remove all traces of interstate 81 through the hillsides of the map. It helps to have aerial photos and topographic maps of the era you are modeling.

 

[Blutorse4792]

Sometime you can only take your time and remove the modern highways by hand in surveyor. I needed to do this on the Laurel Line Route. I had to remove all traces of interstate 81 through the hillsides of the map. It helps to have aerial photos and topographic maps of the era you are modeling.

I too am working with hilly terrain (though not quite Pennsylvania-hilly) so at the very least, thank you for the reassurance that, with determination, it can in fact be done in Surveyor.

 

[JCitron]

Sometime you can only take your time and remove the modern highways by hand in surveyor. I needed to do this on the Laurel Line Route. I had to remove all traces of interstate 81 through the hillsides of the map. It helps to have aerial photos and topographic maps of the era you are modeling.

It is a long process but it is possible and that's what I did to restore a route obliterated by dams. I used aerial photos from www.historicaerials.com along with the old topographic maps to see where things were located and then using the heights shown on the topographic map, I then set my height in Trainz to that and smoothed, dug, and lifted to match. What's interesting is once I got one area, I was able to smooth and interpolate the heights in between and I was able to restore the terrain where I wanted it.

This area is west-central New Jersey near Pompton Lakes through Midvale to Sterling Forest located on Greenwood Lake where the hills surrounding the lake are rising in height as they head up towards Port Jervis and Suffern, NY.

 

[Shortline2]

It should be possible, as I've done it decades ago, in the early times of TransDEM, but, it was not as useful, easy as I had hoped for. I came to TransDEM from an old program called MicroDEM that had a Excel looking grid of numbers and where holes was I could spot them and estimate numbers to go in there instead of those that was in the DEM.

In TransDEM, it was no such thing, I had to use some sort of line tool and from memory it tended not to behave the way I wanted and needed, sadly, as it was one of the big reasons I got TransDEM in the first place.
My project halted quite much but it was a good thing as now a days I have a way to at least more correctly twist my source 1903ish topographic map to fit the more correct way, using Global Mapper and other sources to help navigate my beloved Cripple Creek, Colorado area.

So, I know it can be done, but if it is worth the time to trace and try fix a DEM in TransDEM or inside of Trainz, I can't tell you, as they both have up and downs to them... ;-)

Linda

 

[rwk]

BlackDiamond, it was interstate highways that killed off trolleys, interurbans, and passenger trains like Lehigh Valley Railroad in Feb 1961. Interstates started being built in the 50’s. Part of the Laurel Line is in use from Scranton to the WB ballpark near Moosic by the trolley museum.

 

[JCitron]

BlackDiamond, it was interstate highways that killed off trolleys, interurbans, and passenger trains like Lehigh Valley Railroad in Feb 1961. Interstates started being built in the 50’s. Part of the Laurel Line is in use from Scranton to the WB ballpark near Moosic by the trolley museum.

I-84 and 476 were built right over the ROW too in that area along with the widening of SR 11 and others. Another Trainzer and I visited the area in 2013 and it was a shock to see what's gone and what's left. The what's gone is like being hit by a rock in the stomach.