Welcome to the NavList Message Boards.


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

Compose Your Message

Add Images & Files
    Name or NavList Code:
    Re: Round-off
    From: John Karl
    Date: 2009 May 14, 19:17 -0700

    > Frank wrote:
    > That's right except for one little detail. Round-off error is a random 
    number taken from a uniform sample distribution. What you want for the step 
    size if not the maximum size of the round-off error, but the standard 
    deviation of that. You'll find that this amounts to 1/sqrt(12) times the 
    width of the round-off band. So if you have a dozen numbers added up where 
    you've dropped the tenths, your expected error is only ONE tenth.
    This question is more a matter of navigational philosophy.  I
    subscribe to the old adage that it's most important to know where you
    are not, i.e., DEFINITELY where you are not.  And that's not a matter
    of statistics.  I'm not satisfied to miss reefs only a percentage of
    the time.  So I look at the maximum round off error. Rounding every
    one of 12 numbers to the nearest whole minute could lead to a maximum
    error of about 0.4'x12 = 4.8'.  Why introduce this possible error when
    it's completely unnecessary?
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To , email NavList-@fer3.com

    Browse Files

    Drop Files


    What is NavList?

    Get a NavList ID Code

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

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

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

    Email Settings

    NavList ID Code:

    Custom Index

    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