[OSM-talk] Historical Data in OSM database

Andrew Zaborowski balrogg at gmail.com
Fri Nov 12 20:07:54 GMT 2010

On 12 November 2010 12:28, Peter Wendorff <wendorff en uni-paderborn.de> wrote:
> start_date, as you see in this example, is a generic tag, like e.g. width is.
> Refinements like start_date:construction, start_date:usage; start_date:planning; start_date:disusage; start_date:abandonment are possible - but start_date should not be used to be one of these.

Actually the Sagrada Familia is a good example of the problem with
modifier tags like "width": it's not clear which feature they apply to
if one node or way or relation represents more than one feature.  The
Sagrada Familia is at the same time a building, a place of worship and
a construction site.  The start_date values are different for each,
but I guess if I see these three tags on a closed way + name + a
start_date I'd assume the latter applies to the place_of_worship...
no, actually I wouldn't be sure.  Programs using the data will have
the same problem here, or they will assume it applies to all three,
like "name", which will be wrong.


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