is it illegal to drive with a cellphone in your hand but not talking on it, in New York?

I was driving and needed directions to a store. I pulled over to use my cellphones GPS. Once I was done, I stopped using the GPS function but still had the phone in my hand. A cop pulled me over and gave me a summons for $120 for having my cellphone in my hand and while he was writing me the summons, 3 people drove by me TALKING on their cellphones.