OpenStreetMap
I was visiting my HDYC page today. I always get sentimental looking at my first changeset, a neat feature on HDYC. Here it is with ID 90313. This makes sense to me; I lived in that part of Amsterdam at the time and the timestamp coincides with the day I created my OSM account (while participating in a weekend-long mapping party).
But, when I scroll to the bottom of the changeset page info panel, I see there’s a previous changeset:
How is that possible? If I click on the previous changeset until there is no more previous changesets, I end up at this one, with ID 7671. But that changeset was opened and closed 10 months later, in April 2008.
I always assumed that changesets with a higher ID would also be newer, but that’s obviously not always true. My best guess is that the database got reshuffled in the early OSM API days. Perhaps coinciding with the disabling of anonymous edits in late 2007?
Mysterious. How will I be able to sleep now?
讨论
SimonPoole 于 2022年10月 4日 06:26 的评论
It is just an artifact from when changesets were introduced in March 2009 and they were automatically created from the existing edits at the time.
With other words you are being sentimental about something you never actually did, that is create a changeset in 2007.
mvexel 于 2022年10月 4日 14:02 的评论
@SimonPoole What were “uploads” called before they were called changesets? I don’t remember.
mmd 于 2022年10月 4日 14:37 的评论
An upload is not a changeset… you can have multiple uploads all belonging to the same changeset, as long as you don’t close the changeset.
Before changesets existed, you could still upload one change at a time (which by the way is much slower than the 0.6 diff upload).
SimonPoole 于 2022年10月 4日 14:42 的评论
@mvexel prior to 0.6 there was no grouping of edits. The objects versions had timestamps just as they had now, but as @mmd points out that is all independent of the concept of an “upload” which is not reflected (including in 0.6) in the data model.
mvexel 于 2022年10月 4日 14:46 的评论
Thanks for the history lesson, both!
amapanda ᚛ᚐᚋᚐᚅᚇᚐ᚜ 🏳️🌈 于 2022年10月 4日 16:55 的评论
hahahahahahahahahahahahaha Never look at the history of OSM objects and presume there is logic there. 🤣🤣🤣
If you want a real mind bender, there are OSM objects where a version is created before a lower number version (like an object was created before it’s previous version)
mmd 于 2022年10月 4日 17:24 的评论
That’s exactly the reason why CGImap doesn’t trust the frontend (or former backend) servers to provide accurate timestamps, and delegates all that to the database instead.
jimkats 于 2022年10月 4日 18:23 的评论
This is so deep and philosophical xd