[OSM-dev] Why are so many changeset so large?

[Alex Barth]

Eugene - right, I mean changesets that are geographically large. 

On Oct 16, 2012, at 8:03 PM, Eugene Alvin Villar <seav80 at gmail.com> wrote:

> Hi Alex,
> 
> What do you mean by "large"? Do you mean changesets that span a large
> area (spanning whole continents)? Or changesets that have a lot of
> objects modified (perhaps more than 1000)?
> 
> Based on the examples you provided, it seems you mean the former. Is
> this correct?
> 
> Eugene
> 
> 
> On Wed, Oct 17, 2012 at 7:04 AM, Alex Barth <alex at mapbox.com> wrote:
>> 
>> 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

Alex Barth
http://twitter.com/lxbarth
tel (+1) 202 250 3633