alt Hacker NewsFor others curious like I was, it seems he hired a cartographer to render essentially a set of huge, nice-looking, custom map images with details like hiking trails that Apple Maps doesn't have.
So unlike Apple Maps, which is dynamically rendered, it basically shows image tiles. It allows for a nicer-looking, more detailed map, but affects things like needing separate downloads for different zoom levels, rotation, updatability.
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dzogchen • yesterday at 10:35 PM
I think this may not even be possible because Apple does not give access to the Metal graphics API on Apple Watch to third-party developers.
The use of the cartographer to generate separate designs and the technology used to render/deliver those designs are two entirely separate concerns.
His original map provider offers both vector and raster tile services: https://www.thunderforest.com/maps/outdoors/
A common pattern is to use a vector tile service + style definition directly or to generate raster tiles if those are desired.