[OSM-talk] Preserving History ...

Lester Caine lester at lsces.co.uk
Mon Aug 24 08:05:23 UTC 2015

I'm talking basically about the UK here but I know of similar examples
in the States and Australia and I assume the same rules can be applied
world wide.

There are a large number of structures currently mapped that require
prior knowledge to establish their existence and previous usage.
Railways, canals, buildings and even ancient track-ways. Some of those
routes are protected so that new work has to maintain the viability of
the original. Some are currently used as leisure routes again to
maintain the possibility at some time in the future the original use can
be restored, and some railways and canals HAVE been restored since OSM
started mapping them. So 'abandoned' may not be the right tag, but
neither is 'dismantled'. They both have a legitimate value though if
only for the appreciative user. These structures/objects should be
protected on the map as they often are in law.

Now we come to those situations where an existing object has been
replaced by a new one. One where substantial detail exists on the map
currently but which OVER A PERIOD OF TIME evolves from one structure to
another. There is an outline beyond which nothing changes and elements
within that may be protected much as already described. We can ignore
the work until it's completed, or because of the period of time that
work takes we can map the changes as they happen so routing software is
aware of the current situation.
http://www.openstreetmap.org/#map=16/52.3790/-1.4692 is a perfect
example, where a small roundabout has evolved into a much larger one,
but the new through route is still being excavated. The problem with
this is while it is a good approximation of how work is progressing,
many of the original roads have been deleted and replaced and all the
history relating to them lost. Because 'it's easier to delete and start
again' is encouraged rather than 'preserve the history of development'
where someone HAS already spent the time doing that in the past so much
is being lost! Nothing changed on the ground in 2012 so why was the A46
deleted? The work over three years has been carried out by using the
pre-2012 roads and while the work has evolved beyond that now, the
historic record WAS more accurate.

All I am asking is that people respect the work that has already been
done, and that THE SYSTEM makes sure that the historic record is not
destroyed because it is easier just to delete something and redraw it.
Going back through the history now and finding the original Tollbar
Roundabout history is now a lot of work, but equally, the current roads
are not an accurate reflection of what is on the ground. Phase 4 is due
to come into effect now, with the new bridges in use and that can
probably improved with actual GPS tracks once the new routes are open,
but the date of that changeover should be recoded as the old routes are
removed and the new ones upgraded from 'construction' ... the date the
data is actually changed is academic, but the prep work with a future
start date is what SHOULD happen, just as the underpass route should
become available in June next year.

Lester Caine - G8HFL
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk
Rainbow Digital Media - http://rainbowdigitalmedia.co.uk

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