Lambertus, thanks for quick answer. However, it produced more question than answers.

But on the Wiki page about Copyright and more specifically, on the page about Out-of-copyright maps there is a direct note:

It means that OSM project allows to use scanned maps (that are out of copyright). When I was speaking about scanned maps I used, I meant old maps, not the modern ones (try to find a modern military map in Russia nowadays and I’ll see how long will you enjoy your freedom :slight_smile: ). It means that the maps I used are out-of-copyright because thay were published more than 50 years ago (right after the World War II). So, is it possible to use a vector map derived from such kind of map in OSM?

If yes, than how it can be converted? Of course, it is possible to take a GPS receiver and to walk around the town (well, a city with population more than 800k people is quite large, though), but it will be a complete waste of time. The map I have already has a street names and quite a large number of POIs (around 2k). So I would like to find a way to convert my map rather than to repeat the work.