Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Further on Datum Shifts From Bowditch
    From: John Kabel
    Date: 2002 Jan 18, 7:04 AM

    In the 1995 Bowditch, section 211, it says, referring to the
    replotting of positions from one chart to another, with a datum
    change:
    
    "These datum shifts are not constant throughout a given area, but
    vary according to how the differing datums fit together.  For
    example, the NAD27 to NAD 83 conversion results in changes in
    latitude of 40 meters in Miami, 11 meters in New Yourk, and 20 meters
    in Seattle.  Longitude changes for this conversion are about 22
    meters in Miami, 35 meters in New York, and 93 meters in Seattle."
    
    There is no mention of a "1 mile" datum shift between NAD 27 and NAD
    83.  That would be very surprising if it were true, as the only shift
    of that magnitude I am aware of is the NAD 27 to TOKYO datum shift.
    
    John Kabel
    In around 43 N, 81 W
    London, Ontario
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site