TransDEM and the seamless server

[jukeboxblues]

Sounds like something from a MARVEL comic book, doesn't it?

I received my TransDEM 2.0 this morning a little after 5 a.m. and spent until noon reading the docs and doing the tutorials. My brain is pretty mushy right about now. It seems that no matter how or what I download from that US seamless server I get a file extension that is not recognized by TransDEM.

I did have success georeferencing the google maps but that's about it. I could use someone with a clear head right about now to tell me what I'm doing wrong.

I'm using TS2009, btw. I'd appreciate any constuctive input.

 

[geophil]

Seamless Server is your source for US DEMs. (Don't use it for maps.)

Choose NED DEMs, 1 or 1/3 arc sec. Important: Switch to GeoTIFF as the download format. The data will be packed into a zip archive which you unpack manually after downloading. Inside the package you will find a .tif file. That's your GeoTIFF DEM which TransDEM will be able to open.

 

[Jayturf]

yeah...what he said

 

[jukeboxblues]

There are no TIFF...or any other graphic files in the zip.

 

[JCitron]

There are no TIFF...or any other graphic files in the zip.

When you do the downloads, and the selection screen comes up, choose the button at the top for more options, or something like that - I can't remember what it's called at the moment.

Anyway in there to the right is an option scroll-box that initally says arc-diff. Change that to GEO-Tiff and you'll be good to go.

John

 

[jukeboxblues]

All I am getting in .ADF files and .dat files...no graphic files of any kind. Could it be because I am requesting 1/3 arc (which is available) or should I try the 10m ?

 

[jukeboxblues]

Ok, I got it now. Thanks, guys.

 

[geophil]

In the popup dialog for the download there is a button labeled "Modify Data Request" near the top. Click this and the dialog will offer a huge set of parameters. Locate your "1/3 arc sec" under "Elevation", change the format in the drop down box and save your changes. Then start the download.

Edit: Too late

 

[jukeboxblues]

Where were you on Saturday, Brother? LOL!

 

[Approach_Medium]

Is there an easier method of generating GeoRef images in Transdem 2.0 than using Google Earth?
I have been using this method for 2yrs, and it works very well, but it's a time consuming process.

1) open GE and create lots of placemarks where the railroad tracks are
Save both .jpg and .kmz files
2) open Transdem, and open each .jpg file, then alt-R to open .kmz file
3) Shift-U to create the GeoRef image
4) Alt-S to save the GeoRef image

5) Open the DEM file in Transdem
6) Open each GeoRef file (Alt-O)
7) Save the GeoRef files as .lgb files to make them easier to open in the future.
8) Create poly lines for all tracks, roads, rivers, etc (in separate route files)
9) Export and create Trainz Baseboards
10) Open Trainz route for editing, then open Transdem, and export the track, road, etc files one type at a time.

I don't really have a problem with anything, just wondering if there is a better method of creating GeoRef files than GE.

FW

 

[Vern]

You can use the "tile server" feature built into Transdem to access Google Maps (in aerial view if you wish) and this will download the imagery along your route. The recommended process is to get individual small scale maps for the general area, trace the route then go back to the tile server and download maps along the route.

There is a tutorial in the Transdem Help for using tile servers.

 

[Approach_Medium]

I think I tried the tile server last year, but was disappointed for some reason. It might have been very slow.

I don't know how accurate my route tracings would be if I used small scale maps. GE offers the most accurate and up to date data on railroad lines.

FW

 

[backyard]

Slow it what?

Nah, if Google can't help, just get the Topo maps & go on Further!

You may add to your research by using Track-charts.

If you can define the route, your there, just use the external references to get the route done!

 

[Vern]

The only issue I found recently with the tile servers is if you try and do a long route with a large number of clippings, it kicks you off with an error message. Open Street Map is worth checking as some of their data is quite good - for the UK it even shows disused railways - but the trade off is that the detail isn't anywhere near as good as a decent topo map.

The downside to topo maps is that unless you're spot on with the georeferencing the overlay is sometimes "off" with the terrain, rivers on the side of hills etc. This tends to be more of an issue if you have a narrow "bottom" and "top" so the LL/LR then UR/UL points are very close to each other. Generally, the tiled or WMS maps snap true to the terrain.

The other disadvantage with tiled maps is large expanses of white are hard on the eyes (gave me a migraine the other week) and you can't see spline points or ruler measures very easily. The workround I guess is to identify the particular Transdem texture and swop with a neutral grass one.

 

[jukeboxblues]

This is really getting to be a big headache. I opened the dem and it's about 4 inches wide in transdem. The georef map is 6 times as big and way off to the right...they don't come close to lining up on top of each other. I used the same coordinates for the dem and the GE image.


The one dem I WAS able to load into Trainz2009 had about 46 baseboards and no vector data. Is it suppose to be this hard?

 

[geophil]

If you open only the DEM in TransDEM can you check its dimensions?

UTM coordinates are in metres. The purple coordinate grid also indicates UTM coordinates (if left at the default setting).

This means the UTM coordinates give you some idea of the actual size of the DEM and whether this is plausible.

And what are the rough dimensions of the georeferenced GE image?


The easiest way to get something going is the combination of SRTM DEM data plus Map Tile map clippings. If your current approach seems to lead nowhere you might consider trying these other sources first, just to get the hang of things.

 

[Approach_Medium]

I've always had good luck with USGS Seamless and GE.
Normally, I use altitude setting of about 5000ft for general route tracing, but if I want more detail in areas where GE provides it, I will use 1,000ft.
When I select an area for DL in USGS seamless, I always tick the railroad item under Transportation. This way, I can get an idea of what I am looking at with respect to distance, and the maps are a good size for creation of a route that extends 2bbds each side of the route.

Of course, if you're not talking about USA, then USGS would be useless, but at least Google Earth covers you.

FW

 

[jukeboxblues]

First, let me thank you for your helpful input this past week. I really appreciate it.

Yes, I do use the USGS seamless server and I am at least getting the right type of file now. For some reason I can not get the DEM coverage and the GE image coverage to come even close to matching (size-wise). And I have also been downloading the RR shapefile from USGS which doesn't seem to transfer with the exported route.

At this point I am so frustrated that I am thinking about just importing the DEM to surveyor and using GE painted baseboards to do the route. I had high expectations for this software but apparently its capabilities are beyond my ability to comprehend.

 

[geophil]

Don't give up that quickly.

First of all, both USGS Seamless Server NED DEMs and GE screenshots are quite unlikely to go wrong. If they don't match, one of the two will most probably not have the desired coordinates.

I would guess that the DEM may be the one, in particular it could be too small.

At Seamless Server, have you used the green rectangular mask to mark your download area? (The red mask only defines your view area.)

Did the interior of the green mask show the area you wanted? As fwassner has pointed out, major roads (and their numbers) are quite helpful to ensure your selected region is correct.


On the side: DEM and GE screenshots combined will work for exporting to Trainz, however you won't have a useful ground texture and thus no minimap in Surveyor to navigate around. I recommend to add a map, either the excellent topo maps from Terra Server or more basic Map Tiles. The WMS and the Map Tile tutorials in the manual with show you how to use these services.

 

[jukeboxblues]

Thanks. I'll give that a go tonight. Thanks for your time.