New free DEM data for UK

[metrobus]

Help! has anybody by any chance noticed the massive error near Stalybridge


Don't think thats meant to happen
Edward

[AndyUK]

There's not a TV mast thereabouts is there?

Andy L

[metrobus]

I *think* an explanation for it is that it could be where53N, -2W and 53N join, -1W. Now how to solve it
Regards
Edward

[markandjohn]

Can I just add my thanks for this data. It is utterly fantastic

Thanks again
John

[alanch]

Can I just add my thanks for this data. It is utterly fantastic

Thanks again
John

Thanks John

I know it has 'problems' in some areas, but I don't think that is the fault of the original data. I've had to put it through a convoluted data conversion process using three different pieces of software, and somewhere along that line the artefacts have crept in.

I still hope that Railsimulator.com will eventually build native support for the OS data into the programme, but until they do this is the best I could do.

[D1xxx]

It works for MSTS as well.

Plymouth to Penzance is well on the way, all tracks have been laid and scenery is in the process of being added.

Just a couple of instances of how much better this new data is - the clay pits on the Burngallow branch are represented but the most astonishing detail is at Falmouth where the dock surface is visible!

A quick run around also reveals that I will have to do some major re-routing as the old '90' data is a bit out.

Thanks for taking the trouble to extract and upload.

Regards
DA

[cwgaskell]

There's not a TV mast thereabouts is there?

Andy L

Holm Moss is not far away (I think)

[Acorncomputer]

OK, a technical question for somebody ... where did OS get their contour data from. Has this been collected from satellite data or is this still the data from ground based surveys over the years?

[cwgaskell]

OK, a technical question for somebody ... where did OS get their contour data from. Has this been collected from satellite data or is this still the data from ground based surveys over the years?

The OS web site: http://www.ordnancesurvey.co.uk/oswebsi ... mpanorama/

says: The DTM has been derived from the contours, which were originally generated for 1:50,000 scale mapping.

see the web site for more info

All the best

Colin

[Acorncomputer]

Hi and thanks

It seems that the data was actually created in the 1970's using stereo aerial photography and there could be a plus or minus 3 metre difference between the map heights and the actual heights.

There may also be differences with other ways of measuring heights due the use of different datum points for sea level, although I would have thought that this does not matter too much if all the data you are using does reference the same sea level point.

On the whole it does seem that the OS data is more accurate which will save a lot of route building time.

[cwgaskell]

Hi Geoff,

I suspect that as this data (new to us) is supposed to be 50mx50m resolution, and from a reliable source, it will be a significant improvement on what we had available to us before.

I don't know if the accuracy you mentioned is critical, but it has to be an improvement on the "latest and greatest" that appeared about 15 months ago - the ASTER DEM 1-arcsecond data. On close inspection it was totally useless. There were large numbers of massive spikes, and holes, with valleys and hills that did not exist.

The one key thing is that terrain data does not change much over the years, except for specific areas of costal errosion, so even if it is based on 1970s data it is the best we can get at the moment.

All the best

Colin

[briyeo1950]

I made my first venture into route building today, after countless frustrations and not a few errors on my part I managed to get my small branchline marked out in game and the DEM data installed. Happily going from tile to tile pressing T and watching the hills and colliery spoil heaps appear as if by magic, but after around 10 or so tiles I just keep getting SBHH all the time Is this where my route building ends? anybody able to give me some hope?
By the way many thanks for doing this work with the OS data, It does look very effective


Regards Brian

[alanch]

Happily going from tile to tile pressing T and watching the hills and colliery spoil heaps appear as if by magic, but after around 10 or so tiles I just keep getting SBHH all the time Is this where my route building ends? anybody able to give me some hope?
By the way many thanks for doing this work with the OS data, It does look very effective


Regards Brian

What are the co-ordinates when you get the SBHH?

[briyeo1950]

Hi Alan, I did wonder if that was an issue, I think I read something about it.
Just tried it now, went to Lat 53.00624 Long -1.33655 pressed T and got the SBH. I have most of my 7mile branch with terrain in place its just trying to get the distant scenery set up.

[alanch]

Hi Alan, I did wonder if that was an issue, I think I read something about it.
Just tried it now, went to Lat 53.00624 Long -1.33655 pressed T and got the SBH. I have most of my 7mile branch with terrain in place its just trying to get the distant scenery set up.

As I've explained (a few times) RW will crash if you press T close to 53N - my experiments suggest anywhere between 52.98N and 53.03N. We think, but don't know for sure, that this is a problem with RW and not the DEM data. The only solution at present is the DEM as close as you can to that area and then hand create the terrain in the resulting trench.