Is there a way to control a magic resource node other than building a city near it and building it like a farm?

I researched magic up and got the node channeling and specialization abilities.. but when I moved some champions over a magic node, I wasn't able to channel it or do anything with it that I could see.  I later built a city next to a node and was able to build a structure on it and take control of it, but would like to think there's a way of taking control of nodes without building a city to do so?