Android: Location: Is the returned altitude value measured from inside the building includes the sea level height to building?

I found this link Google Maps Find Altitude

from there, you may receive this kind of result (sample result):

number,latitude,longitude,meters,feet

0,35.612557,139.62865699999998,17.025,55.857

Problems:

1. I am wondering if the 17.025m altitude value includes the sea level height.
2. Is it the returned altitude value measured from sea level

UPDATE: additional problem: What will be the returned 开发者_StackOverflow中文版value for altitude inside the building's basement floor if the floor is under the sea level?

See level height is considered to be 0, and any other altitude, this include building too, are positive values, and oceans floor and depths are negative values. For more details you can read this: http://code.google.com/apis/maps/documentation/elevation/