May 22, 2018 (4 maps)
Although Metro Map Maker officially launched in September 2017,
I didn't include a created_at
field on maps until September 13, 2018.
I made efforts to determine how many maps had been created by those dates based on historical records, but they're only estimates based on the known number of maps on a certain date.
For example, there were 606 maps created by April 11, 2018 (218 days since launch), so I divided those 606 maps roughly evenly across all 218 days.