[OSM-talk] Recording completeness
c.morley at dsl.pipex.com
Mon Jul 16 14:59:27 BST 2007
At SOTM07 it was apparent that there are many organizations ready to use
OSM data when it is complete enough. The need for measures of "quality"
was also raised. So perhaps now is the time to set up a framework where
"completeness" can be recorded. It would provide not only a measure of
progress, but also be an incentive to mappers to literally go the extra
mile. As has been previously noted, well-defined "complete" areas (IOM,
IOW) are a valuable publicity tool.
There are many possible ways of recording completeness and there have
been intermittent discussion of this in the past. (Being aware of all
previous discussion on a list like this is not easy.) But here is one
possiblity, for discussion.
Completeness boundaries would be ways in the the main data base so that
contributors can push the boundaries on a day to day basis. A boundary
of completeness would always be a closed area with the completed area to
the right of segment direction (like coastlines). This means that the
meaning of a boundary would be understandable even when only a small
part of it was visible. It would also mean that the areas couldn't be
tiled (segment directions wrong) but that it would be easy to merge
them, which is what is really needed.
Obviously, there are various levels of completeness, and it would be
necessary to tag the boundary with a description of this, for example
boundary="complete" completeness="public roads". It would be better to
use standard text descriptions like "major roads" or "public roads" for
this, rather than a numerical index. Areas of different completeness
could be nested and could share nodes/segments in part. There would be
guidelines on what the various categories meant. So maybe "public roads"
could mean that >97% of public roads in an area had ways and were named
where appropriate, with enough information for basic routing for cars -
oneway, etc. I think this is the category that should receive the most
I'm not clear whether each area would need to be a single way (necessary
for local rendering?) or whether they could be conveniently split, like
coastlines, and viewed via a low zoom custom rendering in
Eventually it will be necessary for areas to have "guardians" or
"mentors" to maintain quality, but this currently happens informally,
which is good enough for now.
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