[OSM-dev] tile log dates

Martin Raifer tyr.asd at gmail.com
Fri Aug 26 07:56:56 UTC 2016


I'm looking at the OSM tile log files [1] as provided on
planet.osm.org. I can't find any documentation for it on the osm wiki.
While most of it is quite self-explanatory, I'm wondering what the
dates in the filenames actually mean. For example, if one looks at
`tiles-2016-08-23.txt.xz` does it contain all tile access stats of
August 23rd (0:00 UTC - 23:59 UTC), or anything in the 24 hours up to
2016-08-23T00:00:00Z, or something else altogether?

I'm asking because in the above mentioned file, I see quite high tile
access numbers in the areas affected by the recent earthquake in Italy
[2], which didn't happen before 2016-08-24T01:36:32Z (UTC). Take a
look at the visualization of the tile views the last 3 tile log files
in the region:

* tiles-2016-08-22.txt.xz – http://imgur.com/a/ldUrg
* tiles-2016-08-23.txt.xz – http://imgur.com/a/k45LX
* tiles-2016-08-24.txt.xz – http://imgur.com/a/dD1nU

As you can clearly see, the dates mentioned in the logs' file names
don't match up with the actual event.

Could it be that the dates are off by one? Or is something else going on?


PS: The code for making the above visualizations is on github, of course: [3]

[1] http://planet.openstreetmap.org/tile_logs/
[2] https://en.wikipedia.org/wiki/2016_Central_Italy_earthquake
[3] https://github.com/tyrasd/osm-tile-access-log-viewer

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