TransDEM Forum

Sometimes I don't succeed to download all tiles I want at once. If I download some tiles later, they go to a different raster layer. Can I somehow merge them if I want to use them as a whole in all my life?

Can I merge such layers if a tile has a higher resolution than another? What if an area is covered by two tiles of different zoom, can I select which one to keep? I'd like to have more detailed maps along my route and less detailed ones farther.

You can add to DEM various resolution DEMS but there will be a border that you notice. Even if you use DEMS from different sources you will see this border and have to adjust it. For example I live near a border between Canada and USA where I am getting the better USA data for most of the route, but need Canada data for some.

As far as UTM's though you can start with a level of UTM that is lower and stack higher UTM data on top before exporting. This will show a difference between levels but will likely not be as noticeable.

For merging you can use the add DEM and the author also has a great tutorial on merging DEMS. Now if you have routes already built for me personally I use the merge inside of Trainz. You just need to know what to cut out and fit it in like a puzzle piece.

Hope that helps

Sean

Hi Sean,

Thanks for your reply here, too. Do you mean that if I download tiles of lower resolution for a larger area, then some others of a higher resolution for some sections of that area, at the end TransDEM will export the higher resolution tiles, at least if those were downloaded later? Does it also mean that if I have an UTM tile downloaded and try to download another for the very same location, the one downloaded later replaces the older one?

Yes I believe we are on the same page here. I'll try to explain just to be sure.

When you go through the map tile server your selecting a file name that stores both individual images as well as multiple individual images (when selected) along with an index GeoRef raster map. What I normally do is put a name you know perhaps the subdivision or town with the type of map and detail level. It will put a prefix of tilemap which you can keep (doesn't really matter). So I may have a name "tilemap stamford bing15" for level 15 of the Stamford Sub and I'll work my way increasing levels from 16 to 19.

As you save these the screen will only show what that level looks like without other levels. Eventually once you have the UTM's you like and want to combine them you can load in the level 15 after you have erased all raster maps (so you start fresh). The file you are looking to load is not the individual images followed by a number (to differentiate each image) but the on at the top of the series without a number. Then you go up to the next level and load that index until your up to the highest detail (for me it was level 19 though some places had 20 in Bing ortho). I stuck with 19 because 20 was not available everywhere. When you have the composite of stacked image sets you can save this (for me it was Stamford Bing 15-19) for future reference.

At this point however you now have all the UTM's. Transdem will filter this further by the limits you've specified in the other thread I mentioned for the route filter. Keep in mind you can NOT add more UTM's once the route has been created in Trainz.

Hope that helps

Sean

Thanks for the explanation. It was not clear that I can load more raster maps on top of each other.

Anyway, as per your last comment, I had this idea: if I need one more extra UTM tile that I, say, forgot to add when building the route, I can just download and export the tile in TransDEM, then drag it to Content Manager, so I can make it into Trainz, and I "only" need to add that as a scenery object at the cost of careful moving and rotation so that it's properly aligned with the others. Is there anything that would prevent me from doing so? (I know this is far not optimal, but still a way to just add a few extra UTM tiles in emergency.)

I'm not sure to be honest. My method if I needed to would be to delete out the area you need the UTM before doing anything and create another DEM and small route. Then merge it in by way of Trainz.

Thanks

Sean

Thanks, it's something that's worth a try.

I'm late to this discussion, I don't know if I'm helping much.

If you are using Map Tile Servers and the "Map along a path" mode, you have probably seen the ".lgb" files that are produced. These are just a text file list of the Geo-referenced Map Tiles that TransDem reads to find the tile images to put on the screen. As long as you don't introduce non-text characters and don't change the LGB filename extension, you can edit the lgb files with a text editor to add or delete which tile images are displayed.

TransDem does assume that the image files are in the same folder as the lgb file. (I've never tried to include a path along with the filename.)

Thanks! It's not too late since I plan to extend the map some day