Walking around San Diego

So, according to Google Earth, here's my walking distance while I was there:

Day:
1. 5.44 miles (just walking around)
2. 1.83 miles (walking to the conference center and back...got a ride home)
3. 3.66 miles (1.83 x 2 - walking to the conference center and back)
4. 4.08 miles (walking around before my flight left)

That's 15.01 miles, total. When I see that it was only 15 miles, I'm glad I didn't rent a car or anything. That's perfectly walkable.