TransDEM Forum

G'day geophil,

I followed your instructions, as I have done successfully many times before, to make these same alterations/additions but this time, all TransDEM gives me is a blank, black 'map', even using the same coordinates you show in your image...

Jerker {:)}

This illustrated recap map help.

G'day geophil,

...thanks for that, Roland, your "recap" gave me something with which I can work. Interestingly, I did start out using a zoom level of 15, typing in the the latitude and longitude into the "Coordinates" input boxes (which I had done in the past, most successfully) but with no success and I even tried starting with the Google Map tiles, again, without success. Having followed the tutorial, I can now see where I went wrong - I was inputting the latitude value of "51" and the longitude value of "2" (to roughly correspond with your example location, for the sake of the exercise), completely forgetting that all Western Hemisphere values need to be 'negative'. I really am a "silly duffer"...

...again, I must thank you for your patience and tolerance with all the "Dummköpfen" like me...

Jerker {:)}

Just a brief note on a new data source for high-res England DEMs, called DTM or Digital Terrain Model in the UK.

A TransDEM user set me the announcement a couple of months ago: The Environment Agency would make their LIDAR data public.
Here is the download address:
http://environment.data.gov.uk/ds/survey#/download
You will get 2m or even 1m data. Be aware that the maximum resolution for Trainz is 5m.

A fairly recent version of TransDEM is required. But if you already can open O/S Terrain 50, you will be able to open the LIDAR sets. Almost self speaking, the coordinate system is OSGB36.

Edit: Download address has changed, see here: viewtopic.php?p=3671#p3671

They even have 50cm and also some 25cm data for selected spots! (Of not much use to Trainz, though.)

Some background information on the LIDAR data:
http://environment.data.gov.uk/ds/docs/ ... FAQ_v3.pdf
The paper comes with some very explanatory images, to illustrate the different resolutions and the difference between terrain and surface model. While buildings and trees will only be found in the surface model, the "bare earth" of the terrain model still includes man-made structures like cuttings, embankments, dams etc.

For an hands-on example see: viewtopic.php?p=2102#p2102

As a number of users have noticed, the historic O/S 25inch map, digitized, georeferenced and hosted by the National Library of Scotland, has been relocated to a different server: the Amazon cloud. I have updated, corrected and extended the Map Tile settings for TransDEM:
MapTileProviderSettingsOS25inch.xml

If the import doesn't work as expected, delete the "25inch" provider entry in the TransDEM Map Tile client first and import again.

You may still need to combine tiles from more than one "type", i.e. English counties. Also check if there is anything in "England Holes". Gloucestershire has received a second entry. "Newcastle" is also new, just a few tiles. And Scotland is now twofold, still with many gaps, so is Wales.


(Hill shading provided by 1m DTM from DEFRA)

The download address has changed to:
https://environment.data.gov.uk/survey

You can get the 2m and 1m Digital Terrain Model DTM (DEM). Most recent version appears to be named "LIDAR Composite DTM".
You download by tiles of 5 sq km each. Tile raster is OSGB36. Format is GeoTIFF. TransDEM allows multiple selection when opening the files. For this, the easiest way is to unzip all downloaded tiles into the same folder.