This is something of a crossover post. Recent effort in mapping has gone into mastering (by which I mean 'knowing just enough to make it do what I want in this particular instance') v.3 of the Googlemaps API. The aim has been to map locations of the inscriptions of soldiers of the Twentieth Legion. Now up and running. You can see more here.
Pretty standard piece of mapping really, but enough changes from the last time I did it (probably version 1) to have me scratching my head from time time. Getting the database xml formatting right (and the html formatting inside the xml) was half the battle.
Plenty still wrong with it. I don't really need all those layer options. Watercolour is quite fun the first time, but really the Imperium tile set created by the Pelagios Project is my preferred option. Too many coincident points at some places (eg Chester!) for this to truly work; some inscriptions refer to people known from other sources to have served with the legion and are not particularly informative in themselves; I will find a better marker symbol eventually (or revert to something standardised)... but for now it does demonstrate the geographical range of the dataset reasonably well.
