[OSM-talk] Who Did It?

Ilya Zverev zverik at textual.ru
Sat Sep 29 09:24:06 BST 2012


For a long time now, there has been no tool to properly monitor an 
area. Essentially the only way of doing it is to filter changeset 
history by bbox (thanks to Pavel for his RSS filter btw). OWL has been 
turned off, ITO-like visualizations are pretty but unuseful. The simple 
question "who has deleted my road?" turned out to be very hard to 

But there has been a simple solution, that I'm amazed no one has come 
to before. To cut long story short, I present to you the service to 
answer the frequently asked question: WHO DID IT?


It basically downloads hourly replication diffs and stores information 
on affected 0.01-degree tiles, along with extra information, like user 
name or a number of modified objects. Then it is possible to do some 
analysis of that data, to rid users of doing it themselves: which 
changesets should they pay most attention to, where was anything 
deleted, and which tiles have only got new data.

Obviously this service relies only on nodes: other objects do not have 
spatial information on them in diffs; querying the server every time is 
expensive, and keeping minutely planet database is no less costly. I've 
preloaded WHODIDIT with the data since 1st of July, and it's only one 
gigabyte per three months of changes (half of which are indices). Yes, 
you can see what redaction bot has touched.

Also it allows to make RSS feed similar to OWL's. I think everything is 
pretty straightforward, and there is an instruction picture:


The source is licensed WTFPL, and it should be very easy to set up, for 
example, a mirror or a regional version of this service. It's entirely 
in Perl/PHP/MySQL. Check it at https://github.com/Zverik/whodidit

Oh, and if you see no tiles, try zooming in, levels 12-13 should have 
everything. I've not yet figured how to pass error messages to the 
front-end, so there is no helpful message.


More information about the talk mailing list