Getting lost with GPS

I have been in the South (United States) visiting my  daughters. Before leaving Ga. I bought my self a new iPhone. Upon landing in San Diego, I caught a Taxi to an Urgent Med. to take care of a medical issue. Well I found my self in downtown San Diego, needing to get to Old Town to meet my brother and his wife for diner. I pull out the new phone, go to maps and start tracking my location and direction I'm moving. I go about ten blocks, thinking I'm heading toward the water. I sure thought I saw the water through those buildings. This doesn't look right. I stop and ask a passerby, "do you  know San Diego well"? She respones with "yes". "I'm going to Old Town which way should I go"? "Your walking"? "I live in Costa Rica I'm used to long walks". And of course she tell me to go back the way I came, and get down to the water and folllow Pacific Coast Hwy. It took about an hour and a half to get there. Welll worth the walk to get the exercise, since I'd been on three flights to get to San Diego. San Diego is such a beautiful city.