[OSM-talk] Quality assurance strategy?

Jukka Rahkonen jukka.rahkonen at mmmtike.fi
Thu Jul 31 12:19:31 BST 2008


Has anybody been thinking about some general QA strategy for OSM? As soon as
data have been entered to the database they start to rotten. Restaurants and
other amenities come and go, but also roads are changing. Or features may be
poorly mapped from the very beginning. As the project matures more and more of
the work will be updating and improving existing data.

Right now there are some tags which can be used for QA.  Source=Landsat may be
of worse quality than source:gps.  Note=FIXME is a direct indicator of a need to
check the feature. Then there is this new tag, highway=road, that at least
sometimes tells that there is a need to check what kind of a way that linear
object actually is. Some time ago there was discussion about roads which really
do not have names vs. roads which have names but they are not yet entered. There
is also a separate OpenStreetBugs service for informing on any errors on the
map. Tagwatch is another tool that can be used for QA. However, I think that at
the moment it is very hard to find out, let's say, all the features in one city
that needs verification.  Any thoughts about how to make it easier?  Should
there be an annexed quolity control report that is linked to OSM feautures by
feature id?  Or could each tag has an quality assurance tag like True='I know
this information is OK', False='This information is uncertain'? Obviously for
good result QA data should also have time stamps, so that OSM quality
supervisors could easily run queries about pubs whose existence, names and
opening hours have been last checked more than one year ago etc.

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