[OSM-talk] GPX tracing out of copyright maps

[Nick Burch]

On Fri, 10 Nov 2006, Nick Hill wrote:
> I have good scans of the out of copyright 1934 philips road map of London.

I doubt that this map is actually out of copyright. All Ordnance Survey 
maps are crown copyright, which lasts for 50 years. Any other maps will be 
covered by the normal UK copyright rules on literary and artistic works, 
which is 70 years after the death of the last surviving (major[1]) 
author/creator.

So, your map probably had two copyrights covering it, the OS one, and the 
one owned by Philips. The OS one expired 20 years ago, but unless all the 
philips cartographers died within 2 years of making the map, their 
copyright will still run.

One of the main problems with the current UK law is orphaned works. With a 
map like this, you almost certainly can't figure out who the cartographers 
were, hence can't figure out when they died, and also can't find the 
current copyright holder to see if they'll mind. It's a big problem.


If the philips who made the map are still about, you could try asking them 
if they minded you using the map (assuming they still own the copyright on 
it). Personally, I have a 1956 Geographers Map Company map of London, 
which the OS copyright on expires at the end of the year. Some time RSN 
I'm going to talk to them about licensing their copyright for display, and 
hopefully also feature extraction/tracing. We'll have to see if they agree 
though...


> Ideally, I would like a method to draw osm points and segments straight 
> onto such a map with help from the GPS tracks. Maybe as a layer in Josm.

The general scheme is:
* scan in
* straighten the map
* divide up into tiles (eg one tile per map square)
* give the tiles sensible names (eg the tile 4 along from the left, and 2
    up from the bottom might be tiles/04/02.jpg)
* figure out how to turn "15 pixels along and 20 pixels up from the bottom
    left corner of tiles/04/02.jpg" into a position in some co-ordinate
    system
   (eg for NPE maps, each tile is 125x125 pixels, covers 1km, and the
    tile's name gives you the easting and northing) 
* figure out how to turn your position (in a probably randon coordinate
    system) into a WGS84 lat+long
* apply any calibration tweaks for the scan + tiling not being perfect
* output a gpx file

Nick

[1] There's lots of case law on this, about how much of a contribution
      someone will need to have made to a work to qualify for copyright
      protection of their contribution