I wonder if this is necessarily true (either part) for a canal network. I was told by a navigation instructor that "a map is to tell you where you can go, a ch

I wonder if this is necessarily true (either part) for a canal network. I was told by a navigation instructor that "a map is to tell you where you can go, a chart is to tell you where you can't". I have certainly seen diagrams of larger networks of canals/inland waterways referred to as maps rather than charts. And in terms of updating, I wouldn't be too surprised if the people responsible for chart updates weren't super quick to update the information about canals that are only navigable for very small craft.