TransDEM

martinvk said:
For those who want to model other areas of the world, is there a list of equivalent sources that have similar data?
Click to expand...

The TransDEM documentation has a list of the publicly available georeferenced servers available for most of the world, and these servers can be accessed (if I recall correctly) from within TransDEM.

ns.
 
ccowan2126 said:
Is it possible to generate a route WITHOUT UTM tiles? I played around with them on the route and see, now, where they can be raised or lowered. But, they cannot be textured (painted) over, so what good are they? I would just as soon skip the UTM tiles and just texture the terrain like normally. Also, is there a way by playing around with the TransDEM settings to have the track actually follow (with cuts and fills) the terrain? I have the 3D mesh importer installed and would like the track to be placed better so I don't have to tweak it as much.
Click to expand...

Yes it is quite possible to download terrain textures without using UTM tiles. This is how I do it all the time using topo-maps and other maps on various servers. There's a nice tutorial on how to do this in the quick guide, and GeoPhil has recently fixed a problem, due to a server move on the NGS end which allows you to bring in topographic maps into the program again from the National Map server. The instructions are available on his forum under Technical Support.

The alternative is to use GEO TIFF map images, and GEO PDF files. The GEO PDFs are a new thing with the most recent version of TransDEM and are especially useful for historical maps. In fact there is a complete set of historical imagery of the US available.

Click here for some overview instructions and links:

http://nationalmap.gov/historical/

or here to go to the direct download:

http://store.usgs.gov/b2c_usgs/usgs...2&uiarea=2&ctype=areaDetails&carea=$ROOT)/.do

The "Store" is a free download place with the maps.

To use the GEOPDF files, you need to install the freely available GDAL program, which is supplied via a link in the TransDEM manual, as well, as instructions on how to import these into TransDEM.

Here's something that was done using the GEOPDFs:

[
url=http://hostthenpost.org]
0d165b79cab0ae081810420688d784d9.jpg
[/url]

John
 
cascaderailroad said:
... and it takes allot of manual track placement/adjustment to get gradients correct.

Most of the time my gradients are 0.10% to 0.30% and are always much less than 1.75% ... if you just slap track on an ungraded DEM you will have rediculous rollercoaster gradients of uphill 7.5% and downhill of 6.5%.

I have learned how to adjust gradients on a DEM, and it takes meticulous practice, even on the most detailed quality DEM's
Click to expand...

My route does not have much gradient to it, so there is not a lot of work to do. Is there a setting that will LOCK the vertex points of the track height when smoothing terrain height to a track, as opposed to locking each point? Is this something to be done in TransDEM before exporting to Trainz?
 
I believe John Citron explained to you earlier the differences in resolution between 1 arc-sec, 1/3 arc-sec, and 1/9 arc-sec data sets. Each has an inherent error in their height data. As a result, track grades more often than not, need to be adjusted in 'Surveyor' manually. The 'cut and fill' method emulates real life track construction. Close examination of map data (I use USGS 1:24000 7.5 minute 'quad' maps) will reveal surveyed elevation reference points along the track grade. These points will be indicated with a small triangle or an X at each location. Once a Trainz map has been generated and imported into Trainz, open the map in 'Surveyor' and locate the relevant elevation marks along the route. Using your height adjustment tools in 'Surveyor', set each point to the indicated elevation. Remember, a USGS map uses feet an tenths to indicate elevation; 'Surveyor' uses meters; so you must convert each point to meters. Now you can adjust the grade between each point. I find Google Earth images very helpful at this point in determining where cuts and fills are located.
It is an outright fallacy that TransDEM can lay down a ready to run route. At an absolute minimum, one must lay down and smooth the route grade. There is no way around this fact. There is little one can do in TransDEM to avoid this, since attempting to smooth a grade within a TransDEM generated map is difficult and tedious. 'Surveyor' tools handle that job much easier, once the map is exported. There have been several excellent threads posted in the Forums which deal with grades and how to handle them. A Forum 'Search' may help you some.
 
Although I've never used TransDEM, I've used the old HOG program, and it works in a similar manner. Only difference is messing that you do the map elevation work in a different program, and have to do a bunch of math (which I hate) to calculate the height of the terrain.
 
steamboateng said:
I believe John Citron explained to you earlier the differences in resolution between 1 arc-sec, 1/3 arc-sec, and 1/9 arc-sec data sets. Each has an inherent error in their height data. As a result, track grades more often than not, need to be adjusted in 'Surveyor' manually. The 'cut and fill' method emulates real life track construction. Close examination of map data (I use USGS 1:24000 7.5 minute 'quad' maps) will reveal surveyed elevation reference points along the track grade. These points will be indicated with a small triangle or an X at each location. Once a Trainz map has been generated and imported into Trainz, open the map in 'Surveyor' and locate the relevant elevation marks along the route. Using your height adjustment tools in 'Surveyor', set each point to the indicated elevation. Remember, a USGS map uses feet an tenths to indicate elevation; 'Surveyor' uses meters; so you must convert each point to meters. Now you can adjust the grade between each point. I find Google Earth images very helpful at this point in determining where cuts and fills are located.
It is an outright fallacy that TransDEM can lay down a ready to run route. At an absolute minimum, one must lay down and smooth the route grade. There is no way around this fact. There is little one can do in TransDEM to avoid this, since attempting to smooth a grade within a TransDEM generated map is difficult and tedious. 'Surveyor' tools handle that job much easier, once the map is exported. There have been several excellent threads posted in the Forums which deal with grades and how to handle them. A Forum 'Search' may help you some.
Click to expand...

I kinda' figured that. Tweaking the track is certainly MUCH easier than pushing and pulling terrain heights. The TransDEM route I just generated looks pretty good already.

Thanks, to you and everyone else, for your assistance and advice.
 
cascaderailroad said:
... and it takes allot of manual track placement/adjustment to get gradients correct.

Most of the time my gradients are 0.10% to 0.30% and are always much less than 1.75% ... if you just slap track on an ungraded DEM you will have rediculous rollercoaster gradients of uphill 7.5% and downhill of 6.5%.

I have learned how to adjust gradients on a DEM, and it takes meticulous practice, even on the most detailed quality DEM's
Click to expand...

Can you elaborate, just a little, about what process you use to accomplish this? What are the basic steps? I am experimenting with "getting" and "adjusting" Vertex heights and then "straightening" track and "smoothing spline heights", but am probably going about it all WRONG. What should I do first?
 
It was inaccessible yesterday until very late last night. I just got on it a minute ago...still very slow to respond, however.
 
Same here the national map i just get the grey screen and on the ms research map on wms i get a 503 error connection and a error on the usgs maps
 
The server is taken down periodically for maintenance. Unfortunately, they pick weekends to do this when most of Trainzers would be downloading the data. I have also found too that once they finish maintenance, the access is very slow because so many people are downloading data. You might want to try later this evening and see if it is any better.

John
 
USGS Mapping Site

JCitron said:
The server is taken down periodically for maintenance. Unfortunately, they pick weekends to do this when most of Trainzers would be downloading the data. I have also found too that once they finish maintenance, the access is very slow because so many people are downloading data. You might want to try later this evening and see if it is any better.

John
Click to expand...

Thanks, John
I tried again and was able to download a file. I'll remember to use the site during the week after this
Gary
 
Friends,

Please note that some of the USGS servers, besides being down for maintenance on some weekends, go down every night between about 1800 GMT and about 2200 GMT for routine maintenance. For most people, if you want to download a large (collection of) file(s), you're better off getting up a bit early, logging in, and startng your downloads before you head off for your daily activities, letting the download proceed while your computer is (presumably) not otherwise occupied.

ns
 
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