[OSM-legal-talk] license change effect on un-tagged nodes

Frederik Ramm frederik at remote.org
Tue Jul 5 22:37:12 BST 2011


Hi,

Stephan Knauss wrote:
> The mapper who agreed did not only move part of the nodes replacing 
> their information with new one and confirming the existence. 

I think that's the key point here. We cannot know whether the new mapper 
actually had a valid source that would have let him place these nodes.

Imagine: The mapper has collected a GPX track for a 10km long cycleway 
that, partly, followed a riverbank. When mapping, he finds that the 
current river geometry in OSM seems to be 20 metres offset because it 
meanders in and out of his cycleway. He doesn't have a full new river 
geometry; he only knows that in 3 locations along the 10km track, the 
river is obviously, and consistently offset - maybe the river is tagged 
"source=landsat" which would explain that -, and thus the mapper simply 
moves the whole river and all its nodes 20 metres into one direction.

This is a contrived example but not totally unrealstic; I have 
definitely done similar things myself!

Now according to your logic, the new mapper gains sole copyright 
(provided such a thing exists) for the 10km stretch of river, even 
though he never even looked at the Landsat images or whatever.

On the other hand, had the new mapper traveled along the river in a boat 
and collected a GPX track which later led him to do the exact same thing 
- move the whole river by 20 metres in one direction -, then that could 
be said to constitute a "confirmation of the existence" and a 
replacement of the geometry information with new, originally collected 
information.

Now if my example was really outlandish and something like that almost 
never happens, then one could probably say, to hell with it, let's 
assume any moving of a geometry can only be made from original sources. 
But if there is reason to believe that this happens often, then we must 
err on the side of caution and flag the river (in this example) for 
deletion.

Now if the mapper comes along and sees the river flagged for deletion, 
and remembers that he traveled the river in a boat, and maybe even has 
the GPX track, there's nothing to keep him from simply overriding the 
standard assumption of "we will have to delete this river". We don't yet 
have a mechanism for that; currently the mapper would have to delete and 
re-create the river but personally I am in favour of a special, 
temporary license override tag that people could add to an object, 
something like 
"i_have_personally_investigated_the_history_of_this_object_and_i_can_vouch_for_it_being_odbl_clean=true".

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"



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