Here’s a nice HTML web component that uses structured data in the markup to populate a Leaflet map.
Personally I’d probably use microformats rather than microdata, but the princple is the same: progressive enhancement from plain old HTML to an interactive map.
Bruce wonders why Google seems to prefer separate chunks of JSON-LD in web pages instead of interwoven microdata attributes:
I strongly feel that metadata that is separated from the user-visible data associated with it highly susceptible to metadata partial copy-paste necrosis. User-visible text is also developer-visible text. When devs copy/ paste that, it’s very easy to forget to copy any associated metadata that’s not interleaved, leading to errors.
A fascinating examination by Hixie of web technologies that may have technically been “better” than HTML, but still found themselves subsumed into the simpler, more straightforward, good ol’ hypertext markup language.
The follow-on comments are definitely worth a read too.
Hixie has been making changes to microdata in HTML5 based, not on opinion or theory, but on the results of user testing.