TransDEM Forum

Hi.

I'll admit I'm new to TransDEM so it may be something simple I'm missing, but I have successfully created a merged DEM that covers my route in the Highlands of Scotland.

I used the Land Form PANORAMA series to create this. I've tried downloading the OS VectorMap District series that matches the areas I'm modelling as I thought the ESRI Shape format is what I require. I've been following the video tutorials for Canada which worked fine for the first stage but which I can't follow for the vectors. Am I even using the correct map series?

Thanks.
Innis.

OS VectorMap District does not work out of the box for now. A quick debug session (just finished) revealed that all coordinates here are O/S grid. The original ESRI Shape specs required geographic coordinates with the WGS84 ellipsoid but no one seems to care these days.

This is not a big problem since I already added the national coordinate system option to some other supported vector formats. I'll have to do the same here. Couple of days...

Sorry to appear stupid, but does this mean I can't use the O/S data at present to complete my map?

Thanks
Innis.

Not the way Gisa has presented it, not for the time being. But you can and should trace the route yourself, using the built-in polyline editor in TransDEM, called "Simple Route Editor".

Tutorial 7 "Map Tile Services" on page 130 in the TransDEM main manual illustrates the general role of this editor for route building and the reference section from page 60 explains the details. The editor user interface is quite intuitive anyway.

Vector data support has been added to TransDEM a few years ago, but suitable vector data sources were and are scarce. Yes, USGS DLG has been around for more than a decade but it remains rather complicated to use. The Canadians leapfrogged ahead with CanVec in 2009, fully complying to all standards.

I have gone through the tutorial on page 130 and ended up with a vector route on maptiles acquired from Google maps so no O/S data has been used at all. This has given me an .lgb file of the entire route which resembles the figure on page 133.

I'm still a bit confused as to how to combine terrain elevation data with this route. I had managed to create a DEM of the same area but this was taken from O/S data so I doubt the two can be combined.

Thanks.

Yes, they can. As long as all data is geo-referenced correctly, the source of the data is not important. Geo coordinates are absolute, even independent of the map projection. This may be confusing at first, but it's the most fascinating feature of digital maps: it all fits together!

Just open the O/S DEM and then open your LGB file on top of it.

I have success to report! I now find myself looking at my O/S DEM with a Google maptile overlaid on top and then a hand drawn vector route on top of that. Most satisfying.

I feel I am not far from being able to get this all into Trainz now. It is only a case of applying the terrain elevations from here if I understand things properly (although I've already demonstrated that this is not always the case...)

Thanks.

Partial success! I have mangaged to open my new DEM map in Trainz09 which is fantastic. I'm really pleased and also impressed at the power of your software. Thanks.

I have one problem though. There is no texture on the route. If I open minimap, I can see the maptiles but on the route itself, there is nothing but the 5m grid. Have I perhaps missed something? I'm positive I exported everything I should have done.

Thanks again.
Innis.

It looks like the TransDEM ground textures have not yet been installed. See page 8 in the TransDEM Trainz manual.

This is a set of 20 monochrome textures which are used to represent the raster map(s) on the ground. The first minimap for each baseboard is created by TransDEM directly, but to render the terrain properly, the ground textures are needed, too.

Another simple error. Thank you so much for the help.