Had multiple iterations, and put a lot of effort into finding and drawing the maps.
Later we found some support from the community and they promised to provide us with verifiable and trusted map sources...
It's fascinating to see how much more (and more accurate) data your project comprised, but how much better the interface is for this one. Perhaps they can leverage the data you collected for a best of both worlds approach.
We did a similar project and closed it about 5 years ago https://maps.chron.ist/
Had multiple iterations, and put a lot of effort into finding and drawing the maps. Later we found some support from the community and they promised to provide us with verifiable and trusted map sources...
The source code is available here https://github.com/chronhq