How to fix chasms at DEM merge points

[rwk]

Is there any way to get DEMS to merge together seamlessly without creating canyon-like chasms between the merge points? A few times it fused the DEM's together, but most times it creates the chasms. How can you get DEM's to fuse together at merge?

 

[angelah]

DEMs

I use DEMs and they merge perfectly, but the important thing is in the creation of the map, the heights must be exactly right.
A DEM should go to the edge of the baseboard anyway, if it fails to do that then the map is the wrong size and that's maybe creating your chasm...
Check the map size in relation to baseboards.

Angela

 

[stagecoach]

This does not always happen when the builder creates an extra board as an overlap but will happen when the two routes finish exactly on the join. The only solution is to use the flatten ground tool and very carefuly smooth the ground on the grid lines from one board to the next. Dont try and go along the chasm.

 

[Dermmy]

The chasm thing is a known issue to do with the way HOG creates a map not gelling with the way Trainz references two of the board edges. It occurs about 75% of the time when merging HOG maps.

There is a work-around...

Create a 1 - board blank route.

Load the new 'blank' route and merge it with the larger of the two DEM maps in such a way that the blank route is adjacent to the edge which will ultimately be merged with the second DEM, but place the blank route so that it will not touch either of the two DEMs.

Save

Load the just-merged route and merge it with the smaller DEM, Save again.

It has been a while since I did this method and I may have the first merge back-to-front. It may be 'Load the larger of the two DEMs and merge it with the Blank route', but otherwise the procedure should work, it does in 04 anyway!

Andy

 

[rwk]

I'm using TransDEM to create the maps. Even if two sections perfectly line up, the chasm still happens. I might try that blank baseboard trick and see what happens.

 

[HiBaller]

Sometimes chasms happen and no matter what you do they persist. What I do in that case is wind a track (any track) from one side of the chasm to the other with alternating vertex points set about 40 or 50 meters apart ACROSS the chasm. Then use the 'smooth track' tool. It isn't perfect, but it brings up the terrain out of the chasm so you can smooth it better.

Bill

 

[backyard]

A smoother way...

In the terrain menu(F1), place the (pointer, cursor,) azimuth tool on the higher side of the fissure.

Use the get-height tool(Ctrl+g) to get the elevation.

Click on the plateau-tool(Ctrl+p) at the far right of the get-height tool.

This tool will apply an elevation depending upon which direction you drag it...forward for down, pull to you for height.

You will have to adjust the tool when significant elevation changes occur as you ride the fissure. Use the get-height tool, then the plateau-tool.

Adding scenery helps disguise the editing correction.

This also works wonderfully anywhere on the route you wish to hide pointed ground elevations such as along the railroad rights of way. It smooths the jagged edges of cuts.

 

[rwk]

Update: I just tried the blank baseboard trick and it works! There is no break in the seam at the merge point. I guess for each new section I have to repeat the trick to have every section merge seamlessly. I'm doing a 400 or so mile route from PA through Virginia to Gatlinburg Tennessee (big tourist trap town) following I-81 and I have to break it up in sections because TransDEM won't accept too large of a topo map generation for Trainz export, it errors if the topo map is too large. So, I merge the sections together in Trainz and delete any excess boards at the edges to fit the sections together.

 

[AndrewH]

........I guess for each new section I have to repeat the trick to have every section merge seamlessly......

With the "single unconnected baseboard" trick you can keep adding new sections in the one Surveyor session without the chasm appearing. Don't forget to remove the single baseboard before you close Surveyor.

 

[Dermmy]

Update: I just tried the blank baseboard trick and it works!

Glad

Which way round was the first merge? Route-to-Blank or Blank-to-route? And which version of Trainz were you using?

Andy

 

[AndrewH]

Which way round was the first merge? Route-to-Blank or Blank-to-route? And which version of Trainz were you using?

Have the blank baseboard route open and merge the other routes in whatever order you choose. I believe this will work on all Trainz versions.

 

[rwk]

Why does Trainz crash now when I try to merge the larger section to the single baseboard? Trainz just quits, with an error box on the desktop.

If I save a route with the single baseboard, and quit, and reopen it will the trick still work?

 

[JCitron]

This is a sign that TRS2004 has run out of memory and crashed.

When I used to get this, I'd save very often just to ensure that I had things up to a point where I didn't have to start completely over from the beginning.

John

 

[Dermmy]

Try merging the blank to the small route, then save, quit, restart computer before the 'big' merge. That will give you your best chance of enough free memory...

Andy

 

[backyard]

Question...?

As I understand, you are trying to merge a new baseboard with a developed route?

To merge with a developed route?

All I see(in TRS2004) is the ability to merge routes where there are no conflicting(overlaying) baseboards....how wide, measured with the measure tool, is this fissure(metric or standard measurement)?

I see this in TransDEM, but not often & due to the UTM grid, when it does happen it is not more than twenty meters wide...