[Talk-GB] Use of OS OpenData in OSM

Ian Spencer ianmspencer at gmail.com
Fri Jul 23 15:41:15 BST 2010


I don't think that is fair enough if you are going to be legally 
pedantic about it. The basic track was derived from NPE and you have 
adjusted it, by implication you have taken into account the original 
work in two ways: as a validation that the GPS trace relates to this 
item, and also you have got an independent verification that the GPS 
trace is at least in the right ball park. To remove the "pollution" of 
the sourcing, you would need to delete the path and then start anew.

The mass of problems around licensing are exactly due to the pedantry 
necessary to be legally unencumbered. It is an unattainable nirvana - it 
is a fair bet that there are a fair chunk of footpaths in OSM that are 
effectively derived from current OS 25k maps where people may be 
surveying, but have used the OS map to check that their traces are not 
corrupt, or simply have the OS map by their side while they edit. The 
best OSM can hope for is that there is a GPS trail that vaguely matches 
map features to give plausible deniability, and that other "local 
knowledge" type sourcing can be shown to be properly surveyed if someone 
decided to challenge - which leaves surveyors with a burden of keeping 
notes and other evidence.

Given that it is an impossible task to be clean in a volunteer project 
without imposing some rule like "no edit without GPS or signature in 
blood" it would then in turn make sense to be far more pragmatic with 
regard to licensing of OS OpenData than seems to be the case with some 
hard liners.

In terms of goals, it does not make sense for OSM simply to be the sum 
of existing open source data, OSM will only be of worth if it produces a 
product (or products) superior to what is available, or unique in some 
way. The various national cycle maps that are evolving are an example of 
where OSM is producing value that is not available elsewhere. That is 
where the surveying input comes into its own.

Spenny

Graham Jones wrote on 23/07/2010 15:18:
> If I collect a GPS trace of a road that is tagged as say 'source=NPE', 
> I will adjust the road to match the trace, and change it to 
> source=survey.
> That means that unless you look through the history there will be no 
> evidence that it was once derived from another source...but, once you 
> have surveyed it, I don't think it is derived from the other source 
> any more, so this is fair enough?
>
> Graham.
>
> On 23 July 2010 14:42, Chris Fleming <me at chrisfleming.org 
> <mailto:me at chrisfleming.org>> wrote:
>
>     On 22/07/10 16:25, Richard Fairhurst wrote:
>
>         Ed Avis wrote:
>
>             As an aside, I think the 'source' tag is a bit
>             misconceived; it would make
>             much more sense to tag source on the changeset, not on
>             each object it
>             touches.
>
>         Only if you solely use one source per changeset. I'll
>         typically use at least
>         a mix of NPE, OS OpenData, GPS survey and personal knowledge,
>         and sometimes
>         more.
>
>     I tend to do the same - although if I have a track for a road that
>     was previously  source = "not survey" I will generally modify it
>     to match the tracks and either delete the source tag or edit it to
>     be source=survey
>
>     Although I don't think I'm consistent.  What do people tend to do?
>
>
>     One I did recently is
>     http://www.openstreetmap.org/browse/way/4981553/history and shows
>     the evolution of what is initially a traced name = FIXME into a
>     fully surveyed way by 4 people over nearly 3 years :)
>
>     Although this is a good case of where an area appears done and so
>     I didn't visit it, until the the OS comparsion stuff came out. At
>     which point I've discovered lots of missing stuff.
>
>     Cheers
>     Chris
>
>
>
>
>
>     -- 
>     e: me at chrisfleming.org <mailto:me at chrisfleming.org>
>     w: www.chrisfleming.org <http://www.chrisfleming.org>
>
>
>
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>
>
> -- 
> Dr. Graham Jones
> Hartlepool, UK
> email: grahamjones139 at gmail.com <mailto:grahamjones139 at gmail.com>
>
>
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