TransDEM Forum

This is something that's always perplexed me. Whenever I try to have tiles generated for a section which tacks onto a previous section of a route, it always tends to generate the UTMs for the previous section. IE I create a selection for the subsequent portion, and after 30 minutes or however long it supposedly takes, nothing new is generated.

Is there any way at all to have UTMs covering an entire route at once? It would be so much more convenient for someone like me.

The interest in a 360km stretch is sort of still clinging. But I need a way to identify the scenery. I have zoom level 17 selected, due to 18 or long taking forever to generate, for minimal increase in ease of scenery placement.

To make sense of this, my point is that I would prefer at least 70kms covered, in order to not have to add more UTMs later, unless I decide to continue beyond an initial location.

There is a limit to the number of UTM tiles acquired per invocation. It's about 25 without a route filter and about 1000 with a route filter active. The latter is an enormous amount already. Image how long it would take to manually decorate 1000 square kilometres in Trainz Surveyor!

Now, if your route filter path is long and the lateral extension extensive, you may reach the limit before the path is complete. The other reason for not completing is a server no longer responding, deliberately or due to overload. OpenTopoMap is a good candidate for quitting early. In such a case, the easiest way is to duplicate your route path and shorten it (saving the original), so that it won't redo the tiles already there on the next invocation. Note that TransDEM does not keep track here itself.

Do you mean cutting out at a certain point, and creating a second route? I am one of those types that just doesn't tend to give in easily.

My overall intention is to cover a route that is roughly 300kms.

As I mentioned at some point somewhere, MSTS handled insanely large routes with relative ease, including one that had close to 700kms of track.

This line is possibly my favourite line on Earth. But it loses its appeal a little beyond the 300km point, which was a major station at some point, before the line was rerouted well away from there.

I recall when I used maps, the route took forever to load. It actually takes significantly less time with UTMs in place.

Currently I am using the 17 zoom level, with about 8 to 10 poly lines spread apart fairly evenly. With the higher zoom levels, it takes far too long to generate the UTMs, and for very little gain in resolution.

Excuse me if I have inadvertently repeated myself numerous times. It's not intentional.

Something like that. Just manipulate your paths in the Simple Route Editor, so that it doesn't redo the tile you already have.

I tend to prefer to have the resources all ready to go. But not having an option to have the UTMs for a reasonable distance in the route is very frustrating. and disruptive to making any progress.

Unlike some, I have difficulties multitasking, and remembering how to prepare say another 5kms of track, every time I see fit to place scenery objects 2-6 weeks later.

I am still yet to place anything but track in this game, due to the issues with the UTMs for the past 8 months. I intend to model around 40kms of track in the state's west. But can only get about 10kms of UTM coverage in the game. If this was say Open street map, the coverage would presumably be better. I didn't even know about using say Bing or GE as overlays until later on in my current scourge (predicament).

I just wish that TransDEM could cover at least 50kms of track at once. The parallel polylines cover about 1.5 kms each side of the track. But I need to be able to lay track before doing anything. I have endless troubles being able to add any additional UTMs. I have no idea what to do. I have noticed that TRS creates a copy of the route, when you select an option. But the Editing folder remains the same for the route.

I cannot afford to go around in circles for much longer, with my lack of knowledge about TransDEM in general.

And re your comment regarding 1000 square kilometres in the 'Surveyor', I tend to prefer any kind of assistive imagery/UTM/whatever to be about 2.5 kms wide from left to right. IE about 1.25kms each side. I rarely add scenery farther than about 600 metres from the track unless necessary. Is there some kind of memory/resource issue with permitting TransDEM to place more than the specified amount of tiles?

I have found it the UTMs to use far less memory than what Open Street map does. This device can handle a reasonable amount of memory allocation too. When I had routes loading with OSM, it would use over 12GB of RAM and take over an hour to load. With UTMs instead, I think even a laptop could handle it.

I am just expressing my opinion. I am also still puzzled as to how to add additional UTMs to an existing array in a route. For example, the current tiles run out at around Two Wells. I need to extend the coverage by another 150 kms north to enable track laying. Is this doable? If so, it is not clear to myself personally.

@Geophil Could you please reply? I am still puzzled. This is harder than a 50x50 rubik's cube to me.

I can't really give advice here. While TransDEM may be capable of processing enormous amounts of geo data in one situation, it may also easily struck limitations in another scenario. Its overall design is for building your route in modules of reasonable individual size. To keep things manageable for the developer, i.e. me, TransDEM does not do dynamic delayed loading or off-loading of currently unused data. Fortunately, the operating system assists somewhat here, particularly with raster image data. There are some intentional limitations in TransDEM, particularly to prevent unintended excessive processing, but even with them in place you can still crash the program if running out of memory or hang it with an endless high-CPU job.

As a test scenario I created the terrain data for the Brenner Pass route in South Tyrol a couple of years ago, some 50 km long and 10 km wide, with 2.5 m DEM data and ortho-images via the Map Tile client as ground textures, and it worked, see the last two images here: viewtopic.php?p=2143#p2143

Are you saying that it's possible to have what's displayed on the UTMs as terrain textures? I still need to make sense of how to have one route which is 25kms long that will morph into another version of the route to cover another 25-50kms of what I intend to be a 220 km route.

Also, I still cannot make sense of how to add additional UTMs to a cloned version of a route that has no UTMS. The 'editing' folder only covers one route. It's the same with the 'scenery' folder. I can't even get OSM imagery into the route for any reasonable distance.

For example, I save the route, empty the editing folder, export more UTMs, and yet only the previous ones show up. I might have missed something in the manual, which I have been checking at times.

I do understand your point about not overloading the sim itself. But RW/TS can handle large routes, and so can MSTS.

There is one point in the route where the UTM coverage ends at, and I have been trying for days to get it beyond there with no luck. Is it possible at all to have 220 kms of track covered by tiles? It's not just the limit. It's the seemingly absent option to tack new ones onto deleted ones. I have no idea about the process.

I recall last year when I first started with TRS19, OSM coverage for at least 180kms on another line.

Australia unlike Europe is a very large stand alone country, and has long corridors of more than 2000kms in length from city to city. This is why this concept of unimaginably large routes has been brought up here.

Trying to explain a bit the underlying concepts, constraints and features.

Firstly, we have to clearly distinguish the geo data domain in TransDEM and the game engine data domain in Trainz.

In TransDEM we have three fundamental types of geo data:

• DEM, digital elevation models, or also DTM, digital terrain models.
• Raster data, pictures made of pixels, which can represent cartography or ortho-imagery.
  Several methods exist to obtain geo-referenced raster data in TransDEM
  • Manually geo-referencing by assigning individual points on the image to geo coordinates.
  • Obtaining raster image clippings from a web server, using one of the "map tile" or "tile map" conventions.
  • Obtaining raster image clippings from a web server, using the WMS standard.
• Vector data, where TransDEM only supports polylines.

All these have in common that they are bound by geo coordinates. The Earth is not a flat disk but we prefer flat representation in cartography for easy handling, so we have "projections", geo coordinate systems that flatten the Earth. Many different geo coordinate systems exist, because every one has limitations. Flattening the Earth always comes with some sort of distortion, and the goal is to keep that distortion minimal for a specific country/region/area. The internal geo coordinate system in TransDEM is UTM, Universal Transverse Mercator, presumably the most widely spread. UTM divides the Earth into 60 zones along the equator, each 6 degrees longitude wide, and also distinguishes northern and southern hemisphere. Within one zone, distortion is relatively small so that in most cases we can ignore it, particularly in TransDEM. Like the majority of projected geo coordinate systems, UTM is a Cartesian system and its units are meters. Cartesian means that the coordinate axes are perpendicular and each unit on one axis equals the same value on the other axis. So, walking 1000m eastward in UTM coordinates covers the same distance as walking 1000m northward. (With so-called geographic coordinates, the geo coordinate system that uses latitude and longitude as its axes and arc seconds as units, this is not the case.) Maps often have grid lines and since UTM is Cartesian and metric, UTM coordinate grid lines for larger scale topographic maps are typically shown every 1000m.


The Trainz domain, on the other hand, has different, albeit similar types of data:

• Ground, which comprises ground height and ground textures.
• Objects, which are 3D assets of various kind, size and purpose.
• Splines, kind of vector data with special behavior, for railway lines, roads and other linear features.

Trainz has its own coordinate system, Trainz World Coordinates, which all Trainz data types adhere to. Trainz World Coordinates are a three dimensional Cartesian system in metres with an ad-hoc, per-project origin. For ground, Trainz splits its world into small manageable units called Baseboard. Each baseboard is 720x720m. But Trainz has no built-in concept of geo data. (The Trainz World Origin which looks like a geo-reference, is a mere meta attribute.)


The TransDEM to Trainz export does two things:

• It maps geo data types to Trainz data types:
  
  • The DEM is converted to Trainz ground.
  • Raster data is either converted to ground texture or to large Trainz objects which TransDEM calls "UTM tiles".
  • Vectors are converted to splines.
• And it maps UTM coordinates to Trainz coordinates:
  
  • Both UTM coordinates and Trainz coordinates are Cartesian and metric. So, mathematically, the mapping between the two is a simple "translation".
  • But TransDEM also defines a static mapping between the UTM and the Trainz Baseboard grid. This allows seamless merging of modules in Trainz Surveyor.

Note that the term "tile" is used in "tile maps" or "map tiles" in the geo data domain for certain types of geo data web servers and also in TransDEM for the Trainz domain as texture carriers 3D assets, called "UTM tiles" because they are defined and identified by the 1000m UTM grid. These two types of tiles are not related and independent of each other.

Mapping raster data from TransDEM to Trainz is a challenge. We have two options and both have drawbacks:

• Ground textures: Limited by resolution and colour palette. Ground textures in conjunction with TransDEM have a resolution of 1 pixel per ground vertex, 10 or 5m, which is suitable for a map or image scale of 1:50000 for a 10m grid baseboard or 1:25000 for a 5m bit baseboard.
• Anything of a higher resolution can only be used on extra texture carries objects, the UTM tiles. But these are ordinary Trainz 3D assets, add-ons to the terrain, like a building or a tree, only of much larger dimension.

A route builder will only need large scale ortho-imagery for those areas of his project where he intends to model to the detail level, typically the railway track and its immediate vicinity. The UTM tiles serve as a route building aid and will be removed before the route is finished.

No individual route builder will be able to fill 1000s of baseboards with reasonable detail, so generating that many UTM tiles is of no practical value. To build a very long route without spending years on unachievable goals, a possible compromise could be using ortho-imagery for ground textures, as shown in my Brenner Route example. There is a specific ground texture set for this purpose. And you only need medium scale ortho-imagery for that, since resolution is limited. So, no big issue to obtain those along a path with the Map Tile client. Hi-res map or ortho-imagery will still be used with UTM tiles, as the template to actually build the line in Surveyor, but with very limited lateral extent.

There is one other limitation with long routes in east/west direction. Seamless merging is only possible within the same UTM zone. If a route is crossing a UTM zone border the route build has to define a primary UTM zone and ensure that all geo data is projected to this primary zone. TransDEM facilitates this approach, it's mostly automatic, provided the route builder is aware of a second UTM zone involved. Theoretically, this can be extended to a third UTM zone, but only if the primary UTM zone becomes the central zone. This means a maximum route length of about 1000 to 1500 km in moderate latitudes. Beyond that, distortion would become too painful.

That is quite a detailed reply Roland.

I have never thought of using terrain textures as overlay objects. I didn't even know that this was possible. I had a look in the manual. But I couldn't find anything that outlines the process.

It would possibly reduce or eliminate the need for UTMs. But I have never personally seen such a technique being used in TRSxx at all.

And as I mentioned. I am still perplexed as to how add a new array of UTM tiles to a route, after the current ones in there have served their purpose. IE have been deleted, with a tiny overlap maybe if necessary. This is something I need more info on.