-------- Original Message -------- Subject: Re: Question regarding soundings on nautical charts Date: Thu, 3 Feb 2011 13:21:54 -0500 From: erno bonebakker <[log in to unmask]> To: Maps, Air Photo, GIS Forum - Map Librarianship <[log in to unmask]> The gospel is at : http://www.nauticalcharts.noaa.gov/mcd/chartno1.htm at page I ("eye") and http://msi.nga.mil/MSISiteContent/StaticFiles/NAV_PUBS/APN/Chapt-03.pdf at page 19 & 20 For a thorough, modern discussion of nautical charts I would recommend: How to Read a Nautical Chart : A Complete Guide to the Symbols, Abbreviations, and Data Displayed on Nautical Charts, 240p, 2002 by Nigel Calder -- Erno R Bonebakker, mapster & navigator 91 Park St. Portland, ME 04101 207.871.0048 e-mail: [log in to unmask] <mailto:[log in to unmask]>