[OSM-dev] Why are so many changeset so large?
Alex Barth
alex at mapbox.com
Wed Oct 17 00:04:37 BST 2012
I really like how activity streams shows easy-to-understand changes on the map using changemonger [1,2]. At the same time it creates an alternative break down of changes that is more granular than changesets. This diverts attention from _comments on changesets_. This is not ideal in my mind - these comments on changesets have great potential to become an even more important communication channel in the future.
I understand activity streams / changemonger suggests a broken up view of data changes because many changesets are so large that they are effectively not meaningful. I'd like to understand better why these changesets are so large.
Unscientifically digging back on the history of today, I'm seeing many many changesets that seem like they could be just as well much smaller - both in the sense of geographic extent and number of elements - I don't want to call anybody out here, but this is what I found:
- http://www.openstreetmap.org/browse/changeset/13514072
- http://www.openstreetmap.org/browse/changeset/13523015
- http://www.openstreetmap.org/browse/changeset/13508818
I understand that there will always be cases where a large changeset makes sense (e. g. bot changes), but it seems that we have many unnecessarily large changesets that make changesets a not very useful granularity for looking at data history.
My questions
- What are the recommendations for change set sizes?
- Are there technical reasons why changesets should tend to be large? Are they expensive on some level?
- Could editors encourage users to do more and smaller changesets?
- What else could be done to encourage smaller changesets with meaningful comments?
[1] http://lists.openstreetmap.org/pipermail/rails-dev/2012-October/001086.html
[2] Click on 'activity' here http://suncobalt.dyndns.org:8081/?lat=51.61&lon=22.44&zoom=7&layers=M
Alex Barth
http://twitter.com/lxbarth
tel (+1) 202 250 3633
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