NOAA Nautical Charts

Nautical charts show water depth, shorelines, prominent topographic features, aids to navigation, and other navigational information.

note: Ocean depth soundings are in fathoms and refer to Mean Lower Low Water. Heights of rocks, bridges, landmarks and lights are in feet and refer to Mean High Water. Contour and summit elevation values are in feet and refer to Mean Sea Level.

source:

info:
http://www.nauticalcharts.noaa.gov/mcd/learn_aboutcharts.html

legend: http://www.nauticalcharts.noaa.gov/mcd/chartno1.htm