UK topo maps online

[Roland Ziegler]

As Zusi route builders focus on accuracy, topographic maps are a useful resource.

I found OS topographic maps with coordinate reference from two sources:

http://www.streetmap.co.uk/ offers the OS 1:50000 in rather large tiles. Search for a place name, zoom in on the map to the maximum and click "large" (if your screen is big enough). The map is enlarged to about 1:20000 for easier reading. The light blue 1000m grid shown is the British National grid, helpful for georeferencing.

OS itself offers maps at http://www.ordnancesurvey.co.uk/oswebsite/getamap/
The tiles are much smaller (and not enlarged) but maximum zoom retrieves the 1:25000 map. They also show the British grid.

Keep in mind though that for all OS maps certain copyright restrictions apply.

So how can these maps become useful for Zusi route building? The tool for that is TransDEM, either available from my website as an update for the latest edition of the Ziegler-Tools or bundled with upcoming Zusi CD 13. Little drawback: no English documentation yet.

TransDEM accepts bitmaps for georeferencing. It also supports the Britsh National Grid (OSGB36). For each bitmap (a topo map tile image) the user picks a few well known coordinates and lets TransDEM do the rest - that is: georeferencing and transforming the image to the UTM system.

The user can then overlay DEMs (SRTM for the UK) and will also be able to trace railway lines and save them as a raw route for Zusi - map copyright permitting. The latter feature is currently being field-tested and will be integrated in the next release of TransDEM.

[Oliver Lamm]

And that what its look like.
In the screenshot the following material was used:

Top25 map
Metrolink Plans 1:1250
STRM DEM
Raw route based on the metrolink plans.

Oli

[Roland Ziegler]

Bury Terminus

[Jpl]

Hmm.... would someone like to write a english summary on this process, please?

[Oliver Lamm]

Jpl,

please send me an email to mail@oliverlamm.de

Oliver

[Roland Ziegler]

Geo-referencing of http://www.streetmap.co.uk/ topo maps made easy:

As mentionend in September, this site offers the OS 1:50000 map. Search for a place name, zoom in on the map to the maximum and click "large" (if your screen is big enough, i.e. 1280 x 1024 or more). The light blue 1000m grid shown is the British National grid (OS grid), helpful for geo-referencing.

All 1:50000 map are tiled into multiples of 1 km, the regular map is 3 x 3 (600 x 600 pixels) km, the large map is 5 x 5 km (1000 x 1000 pixels). All tiles match exactly the OS grid squares. On the left and below of each map there is a coordinate field. These coordinates are OS grid by default, too. They point to the centre of the map.

One of the (upcoming) latest features of TransDEM will be a simplified geo-referencing function for special cases, where the corner points of a rectangular map have known coordinates, just like here.

In our case the SW corner is the centre point minus 1500 or 2500 m (reg or large) map, and the NE corner is the centre point plus 1500 or 2500 m.

Other helpful features in upcoming TransDEM 1.0 for this task will be:

• Pasting of bitmaps from the clipboard: Alt+Print on the browser window, then Ctrl+V in TransDEM to get the web page contents
• Cropping of the image within TransDEM before geo-referencing.

[Jason-M]

Well I have converted most of my maps and pieced them all together, though I have problems with one map which I have asked for help with.
So I have my maps ready for my route, that's a start.

[Steven G.]

Hello,
I am working on a small ~ 40km long section of line in Australia. I have successfully used TransDEM to georeference a bitmap image saved from http://www.multimap.com.
eg:

http://www.multimap.com/map/browse.cgi? ... imap.y=199

I saved the image (by right clicking), then returned to the online map and noted down the coordinates of three identifiable points in the top left, top right and bottom left of the image. When the online map is clicked it provides the coordinates of the centre point. I then used an online coordinate convertor to change from Lat/Long to UTM coordinates. I then used TransDEM to georeference the bitmap. It has worked very well so far.

Regards,
Steven.

[Roland Ziegler]

Hello Steven,

good to hear you have been successful with TransDEM, even without any English documentation.

There is a little feature in the TransDEM geo-referencing dialog, which may be helpful in cases like yours where do have lat/long coordinates but do not have their UTM counterparts: With the coordinate system set to UTM, you can enter lat/long values directly into the UTM fields. TransDEM tries to recognize and distinguish these from UTM values. Several formats are supported.





To those of you working with the British OS grid: this seems to be a bit tricky in the beginning. Remember: all coordinates are in metres and should either have 5 digits plus the grid square name or 6 digits without the grid square.

[Michael_Poschmann]

good to hear you have been successful with TransDEM, even without any English documentation.

It's even possible to use the tool without reading the German documentation... You just have to spend some money on phone calls to Roland.

Regards
Michael

[Steven G.]

Hello Roland,

Thanks for your reply. I didn't realise you could input Lat/Long directly into TransDEM, that would make it very much easier. I will try that.

To this point I have been reasonably successful in laying down a basic route using the Absteckrechner and have used a SRTM DEM to build the landscape. I am now playing around to see how best to combine roads/rivers into the landscape.

Thank you very much for your work in creating the editing tools such as the Absteckrechner. It makes it very easy to lay accurate and realistic Zusi track.

Regards,
Steven.

[Roland Ziegler]

Hello Steven,

thanks for this kind feedback.

I assume you updated Absteckrechner to the current version 1.9 for the latest features?

[Steven G.]

Yes, I am using version 1.9.

Regards,
Steven.

[Roland Ziegler]

Good. With some luck TransDEM 1.0 will be availbale around Easter.

I still have to find and eliminate some bugs with Australian DEMs.

[Roland Ziegler]

An interesting source for large scale maps of England:

http://www.pcs.planningportal.gov.uk/pcsportal/

Click [More] in opening dialogue, then click [Select a point] or [Select an Area], zoom in and keep zooming in. You will be amazed.

Maps are aligned with the O/S grid. Coordinates in the status bar.



(link source found in a UK forum)

[Oliver Lamm]

Wow

Oli

[Jason-M]

Very interesting.
Thanks Roland.