TransDEM Forum

Hi,

I am newbie into this so i need your help

I did create in the past some DEM maps for Trainz Simulator using Global Mapper but i was not satisfied about the result so now i am trying to create some more accurate and also insert Google Maps images, of course using TransDEM. The problem is i don't know where to start. I read some tutorials and all i managed to do was to transform a .hgt file into a .dem file and merge some .dem files (although i don't think this is very important for what i want). I also tried to play a little with the program to get familiar and after that i started reading this tutorial http://transdem.de/download/public/misc ... ta_mbk.pdf . The problem is that when i am loading a .tif file i get an error: DEM operation aborted. What am i doing wrong? The file size is indeed quite large (i think) - about 67Mb. The .tif's that i am trying to load are downloaded from here http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp

Also, can someone give me a hint regarding some websites where i can find maps of Europe/Eastern Europe?

If you need anymore information let me know, right now i don't know what other things are worth mentioning.

Thanks

Later edit: started now the TransDEM Muengsten Tutorial and just realized one of the mistakes. I was clicking on "Open DEM" and loading the .tif. Now i clicked on "Open original raster map" and the .tif loaded but it is too big it seems (see picture below)



How do i resize it? And if i do that would that affect the quality of the future DEM map?

Further edit: managed to export and make a DEM in Trainz. Simply downloaded some .hgt files from here http://dds.cr.usgs.gov/srtm/version2_1/SRTM3/Eurasia/ , selected a smaller area and exported as a DEM map for Trainz. It did worked

Now i need to find out which ares from there represent Romania and how can i merge a few pieces to get a bigger DEM. Slowly i am starting to learn this thing

If I understand you correctly you had some sort of success with the SRTM DEM now.

Always important: "Muengsten" tutorial first (#1 in the TransDEM Trainz manual).

Then try the Map Tile tutorial (page 130 main manual) for the easiest way to get a map which you can use as ground textures for your route.

Ok thank you, i'll do the 2 tutorials . I did parts of the Muengsten tutorial but i will do it completely. Will get back with a status after

Ok, i started to read the documentation and make the tutorials.

So, the first question is:

In the "Tutorial 1: Georeferencing a Raster Map" , i have to click on the SW corne of the map end enter some coordinates (see photo below)



But when i click on that point, i get totally different coordinates (see photo)



Now, my question is, where are the coordinates from the tutorial taken from/calculated ? In the tutorial i enter them manually, and after that the other points (SE, NE) appear as in the tutorial. But if i want to georeference a different map than the one in the tutorial i will not know what coordinates to input there. Am i missing something?

Also, i tried to make this tutorial again. http://transdem.de/download/public/misc ... ta_mbk.pdf

I have some tif. maps of Romania downloaded from here srtm.csi.cgiar.org/SELECTION/inputCoord.asp . I have resized the images, reducing them to half. When i do the steps like in the tutorial where a similar .tif image is loaded i get this error.

Tutorial #1 illustrates the basic principle. However, for this to work you need a suitable map, one with coordinate values.

In my earlier reply I recommend to try tutorial #7 "Map Tile Services". This is a more automated approach. The TransDEM Map Tile Client uses the same georeferencing methods as shown in tutorial #1, however, the map tile client processes all the numerical coordinate valued itself, without the need for user input.

After you completed tut #7 check the different Map Tile providers for the area of your route. I would expect some sort of usable map from at least one or two of them.



This GeoTIFF variant of SRTM DEMs should generally work. However, you must not modify the downloaded tif file in any way before opening it in TransDEM. And you must open it as a DEM.

There can be confusion here. TIFF is an image file format by nature. GeoTIFF adds geo coordinates to it. It ist often used for cartographic maps and aerial images but it can also be used for DEMs. The contents of a DEM GeoTIFF, however, is totally different to that of a cartographic map GeoTIFF.

In TransDEM, theoretically you can open a tif file as a DEM or as a raster map, but both are two completely different pair of shoes.

Furthermore, you cannot tell from the name whether a file is basic TIFF or enhanced GeoTIFF. Both files have type .tif. If you modify a .tif file with an image editor, the GeoTIFF information is likely to be destroyed.

Thanks for your answer ( i know i probabaly am a pain in the ... but i only used Global Mapper until now and only followed like a robot a tutorial so i am not very familiar with all the terms and tehniques...but i am willing to learn how to use TD )

Anyway i think i am getting close. I managed to get to this.



It's a dem map, actually a few merged dems (a few days ago exported one into trainz and it worked fine, just that it was non textured) and over the dem map i have a photo from GE taken using the Map Tile Servers. Now, how do i keep this photo and add another? Because each time i use the Map Tile Server and look for a new location, the previous picture dissapears

Also, is there any need/possible to change the opacity of the GE image if i intend to export dem&ground textures or is it ok like this?

L.E. Solved the problem with the photos, they disappeared because i was changing servers , it seems if i keep the same server i can add multiple pictures

Another difference between DEMs and raster maps/ortho-imagery in TransDEM is that you can and often will load more than one at a time. (They have to be in the in georeferenced state.)

The TransDEM Map Tile Client has a function to acquire images along a path, a good example to show how multiple images are handled in TransDEM. If you follow tutorial #7 to the end, i.e. do all the parts, you will learn how to use this functionality.

Another important remark: Throughout my examples you see the exclusive usage of maps, not aerial images, for Trainz ground textures.

There is a technical reason for this. The Trainz route files have a limitation for the number of different ground textures you can use in a route. In the end, you are obliged to work with monochrome textures. Disadvantage is limited resolution. For a sufficiently sharp appearance on the ground and in the Trainz minimap you will be restricted to a scale of 1:50,000 for a Trainz 10m terrain grid and 1:25,000 for a Trainz 5m grid (from TS2009). At this scale aerial photos (aka ortho-imagery) do not provide enough detail to be of much use for route building. Therefore, as a general rule: Use cartographic maps for ground textures. If large scale aerial photos are needed for yards etc, let TransDEM create UTM tiles objects, texture carriers that do not have the scale restriction.

Finally managed to figure it out

A map with google aerial view



and the same map with street view



Thanks for all the help. Now i will read again the manual and tutorials and try to improve what i already aquired

Looks all right to me now.

Why do i get this error message?