A question for the terrain creation experts:


Addicted to TranzDEM
Is there a way to use TranzDEM with existing elevation data and an historical topographic map, using the contour lines on the map, to erase a lake where historical rails are under water?

basically, can TranzDEM or MicroDEM (or any other open and free GIS software) "Read" and produce a terrain from contour lines?

I guess I really know the answer to this, but maybe someone has an idea of getting the results i'm looking for. I am really only interested in creating historical routes, and I need a way to replace the big flat spot of a lake with the original terrain from before the dam was built, perhaps using information from topographs that were made before the dam was.


There is a function in TransDEM to "create via tracing contour lines" but I never been fully happy with the result. Doubt it is TransDEM its fault though, more me seeking perfection, seeing I still, decades into this yet have to "gone on" with my old 1903 topographic map unto modern ground.
During that time I've learned much more that my old map is not "drawn right" and also the whole area it is has some issued towards modern time, even seen that in the DEM as artifacts and borders come through as something has shifted in the land.

But, what you ask should be possible.

I also done something similar in MicroDEM, there it was "poking around with columns of numbers" while in TransDEM you have to trace the lines and don't get to "see the numbers" making up the DEM, like I did in MicroDEM.

For your use, adding in the "below surface" terrain I think TransDEM will be of use to you, that is, if the old map has a file format that TransDEM can read and open at the right location.
Right now I am certain TransDEM can't make a map fit any given location like I can do it in Global Mapper, but I "fixed" such map in Global Mapper and put into TransDEM, no problem.

I hope the above is not to complicated to follow and that it helps you believe in that what you want is possible, because it is if you want to put in the work to get the result.

For my own project, I am each year getting closer to my coal, twisting and messing the format of the old USGS map, as I have now some maps with overlapping info I can use and have shafts, street corners and rail lines to compare and hence I get more and more of the old map "right".
Issues for me are the outlaying areas, but for a lake it should not be a problem.