Mapping the general plan of a city

Has there been such case of OSM use?

There’s a group of volunteers who’d like to map the published raster images of our city’s general plan and make a website with the map.

Right now I’m thinking which way to take:

  1. Do it with JOSM and submit the data into OSM, then render the general plan from this data with some special rules. This will require custom tags and probably a bot to fix them.
  2. Make a standalone site using OSM tools and editors, store the data there, and exchange data with OSM.

They have to pay attention to the copyright of the original map!

Do they have permission to do that?

It’s in public domain.