My first guess would be that this is using OSM data, but I didn't see any mention of that on the site and didn't see any OSM copyright notices on the images. Could one of the creators explain where the map data comes from?
Yup, totally OSM data. Going to add attribution to them in our Our Story section right now. Totally missed that, but happy to give credit where credit is due. Thanks!
... This credit needs to appear in a place reasonable to the medium you are utilising. In other words, you should expect to credit OpenStreetMap in the same way and with the same prominence as would be expected by any other map supplier.
... For a printed map, the credit should appear beside the map if that is where other such credits appear, and/or in the "acknowledgements" section of the publication (often at the start of a book or magazine).
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EDIT: looks like this only applies to OSM maps, not data. What's the difference between a "Produced Work" and a "Derivative Database"?
Produced Work is an output that uses but does not alter the OSM data. So you can use an OSM database with your own data overlaid on top. These lovely paper prints would be a produced work. One basically does not change the OSM data, you just produce things with it.
Derived database is where you adapt the OSM data with your own data, or perform some kind of manipulation of the data For example, vector simplification or calculating the road lengths and adding that into the data, or merging addresses from one dataset with the polygons from OSM.
