Oh the joys of paper maps - not

[AntonyVW]

Having taken the plunge when I first got trainz that I would create a route of my own, I decided to do something I am familiar with. Following the excellent tutorials on http://homepage.mac.com/doug56/MBC/ on how to create basemaps, I decided to make mine from a current OS paper map. Gradually over the last few weeks I have patiently scanned in sections of the map and then used cropper to get chunks of those scans all scaled correctly.
All was going well. That was until today.
Let me explain the route I have been following. Starting in the north east of my chosen area (north Worcestershire), the line splits into 2 different directions at Stoke Works. The westerly track heads through the town of Droitwich and on south to the city of Worcester where it splits again. One of these lines (Shrub Hill) - the southerly one - continues south through the city turning east.
back tracking a little to the original split in the track at Stoke Works - the easterly track heads south - bypassing both the town and city to meet up with the other track described above south of the city.
Easy one would say - nice and straight forward one would say (ignoring all the sidings etc).
Oh no!
I have made sure that I scanned every portion of the map at the same resolution and then cropped each section to the same specifications. But when it comes to joining the last 2 sections together I find that the tracks are completely out of alignment. - not just by a fraction of an inch but like 1.5 inches or so. Im guessing that would be a couple of hundred feet in reality or at least it feels like it
An engineer Im not.
Moral of the story? use a scanner that can cope - or better still use a map that is already digitized. Now I ask myself where did I go wrong?....
If I had scanned every inch of the map and filled in every unnecessary section I would have spotted the error earlier. But as the tracks diverged I left big gaps in the middle. It would not be seen from the trains so it was not needed.
To be honest the greatest issue in doing things this way is ensuring that every section of the map that is scanned is completely square. If there is even the slightest error in this it will show up eventually as it did for me. From Stoke Works in the north of my route to Worcester in the south is in the region of about 14 miles. Im just glad that the engineers who built the real line where more accurate than me.

 

[Vern]

To be honest scanning paper maps is a little cumbersome. You would be better off taking screendumps from Streetmap or the OS overlay in Live Maps and pasting these together in a paint programme. However recommended to go one step further and invest in Transdem for a very modest fee and this programme will talk to various web mapping services and overlay the mapping on the DEM for you and create the terrain. It still takes a bit of work but you will never want to scan another map again!

 

[Zorronov]

I agree with Vern. Transdem is the way to go.

Cheers,
Fred

 

[AntonyVW]

To be honest scanning paper maps is a little cumbersome. You would be better off taking screendumps from Streetmap or the OS overlay in Live Maps and pasting these together in a paint programme. However recommended to go one step further and invest in Transdem for a very modest fee and this programme will talk to various web mapping services and overlay the mapping on the DEM for you and create the terrain. It still takes a bit of work but you will never want to scan another map again!

Transdem is on the list of must haves. Off on holiday with the grandchildren first though next week.
I do agree with what has been said though. My post was really a warning to those who have never tried it before - like myself - of the pitfalls involved in scanning a map.
Having never done anything like this before, I wasn't aware of the online maps available (apart from google earth and google maps etc). Im still not sure what is really available for the UK as most references I see seem to be for our US cousins.
I have found the old maps website which is of great interest to me, and I am now aware of what OS has put up for free. However Im still trying to find programs that will read some of the data. For example from the OS website I have downloaded the following:

landform panaram (so) - unfortunaltely it does not seem to want to download all the data I want. (waiting for them to find out why).
OS street view (so)
OS vectormap district (raster)(so)
OS Vectormap district (vector) (so)

Now some of the formats included in these files have extensions such as .tab - .tfw - .prj - .shp or .shx and as yet I have no idea how useful that data will be till I can read the files.

still the future is bright

 

[geophil]

Having taken the plunge when I first got trainz that I would create a route of my own, I decided to do something I am familiar with. ... I decided to make mine from a current OS paper map. ...
I have made sure that I scanned every portion of the map at the same resolution and then cropped each section to the same specifications. But when it comes to joining the last 2 sections together I find that the tracks are completely out of alignment. ...
Moral of the story? use a scanner that can cope - or better still use a map that is already digitized. ...

Paper maps per se will not necessary create problems. Particularly not if the maps are topographic and carry a proper coordinate grid. OS maps will definitely fulfil all criteria. The "Landranger" (1:50,000) and, even better, the "Explorer" (1:25,000) series are optimal for Trainz route building purposes. (1:25,000 from TS2009 onwards.)

But these maps are also available online, as Vern has pointed out. You don't need to scan the maps yourself.

As I understand it, your plan is to revive the heyday of the salt industry, a hundred years ago. Do those current OS maps reflect enough of the former glory? Or would it be better to use older maps? A couple of weeks ago, Vern has pointed out this site: http://www.sabre-roads.org.uk/maps/.

Have a look at those. These are scans, too. But someone has already done the scanning for you, and, quite important, the so-called geo-referencing as well.

Geo-referencing is the little extra in digital cartography. Using a suitable software tool it enables the user to combine maps, ortho images (aerial photography) and DEMs (digital elevation data) without the need for cumbersome manual adjustments.

 

[geophil]

landform panaram - unfortunaltely it does not seem to want to download all the data I want. (waiting for them to find out why).

This is the height data. The predominating term is the American acronym DEM for Digital Elevation Data. "Elevation" is not much used in that context in British English. You have to download the entire set but you will only need a few squares for your route.

OS vectormap district (raster)

This is a vector map by nature. It has been rendered to raster form (raster = image). It is less detailed than the standard OS Landranger and Explorer series.

OS Vectormap district (vector)

This is the vector map in its original form.

Now some of the formats included in these files have extensions such as .tab - .tfw - .prj - .shp or .shx and as yet I have no idea how useful that data will be till I can read the files.

Admittedly, those file types and formats are made for cartography software, not for human readability.

 

[AntonyVW]

Paper maps per se will not necessary create problems. Particularly not if the maps are topographic and carry a proper coordinate grid. OS maps will definitely fulfil all criteria. The "Landranger" (1:50,000) and, even better, the "Explorer" (1:25,000) series are optimal for Trainz route building purposes. (1:25,000 from TS2009 onwards.)

But these maps are also available online, as Vern has pointed out. You don't need to scan the maps yourself.

As I understand it, your plan is to revive the heyday of the salt industry, a hundred years ago. Do those current OS maps reflect enough of the former glory? Or would it be better to use older maps? A couple of weeks ago, Vern has pointed out this site: http://www.sabre-roads.org.uk/maps/.

Have a look at those. These are scans, too. But someone has already done the scanning for you, and, quite important, the so-called geo-referencing as well.

Geo-referencing is the little extra in digital cartography. Using a suitable software tool it enables the user to combine maps, ortho images (aerial photography) and DEMs (digital elevation data) without the need for cumbersome manual adjustments.

Thanks Geophil for the explanations of the file formats. Much appreciated. I also had a look at the website you mentioned that Vern posted about. I think I need to do some more investigating there
As to what the Os maps show in relation to what I hope to achieve, no they show me where the main lines were but nothing remains from the industrial areas. I have been using the old maps website for that. What Ive been doing is using the OS maps to lay the main track and then using the old maps and overlaying them on top to give me the extra details. A bit long winded I know but its been fun learning.
Hopefully when I get back from my holidays next week I shall go ahead and purchase transdem and see just how far out my track laying is. Hopefully not to far. Problem at moment I dont know if its the westerly tracks or easterly tracks or a combination of both being out which has casued the error.