I actually gave many inputs to the map apps developers to make this travel method possible. So definitely only possible in recent years, and no internet is needed (save roaming fees, internet fees, etc).
So just pull out phones, and you can know where you are and can easily decide where to go, what are nearby, what to do, etc. The local guide was impressed that I knew more about places in the city, than him :)
Different pin colors denote different types of places: food, places, hotels, clubs, spas, etc.
You can easily remove pins and add your own places as well.
I am mostly focus on great food and great places to go.
Try it out. It is the best method to travel. Definitely better than any other travel guide :)