DayOne map is a template for dayone_export that produces a interactive OpenStreetMap-powered map using Leaflet from your Day One entries.
Using it is super-simple, as long as you have a basic grasp of the command line. With dayone_export installed on your computer, enter the following in Terminal to build the map in the current directory:
dayone_export --output map.htm ~/Dropbox/Apps/Day\ One/Journal.dayone --template-dir . --template map.htm
To include photos, make sure to copy the photos folder from Journal.dayone into the current directory.
This is the result of just a few hours' work so far - definitely a work in progress. I would post a demo, but I'm not too keen on sharing my personal diary with the rest of the world...