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
    Re: Calculate new coordinates given bearing and distance?
    From: Lars Bergman
    Date: 2021 Nov 1, 15:16 -0700

    Tony,

    With the same nomenclature as Geoffrey Kolbe used,

    Lat1 and Long1 are your start latitude and longitude. 
    Lat2 and Long2 are the new coordinates at the given bearing and distance
    Diff will be the difference between Long1 and Long2
    Dist will be the distance in nautical miles. A nautical mile is equivalent to one minute of arc on a Great Circle, so this is converted to degrees in the formulae by dividing by 60
    hav(90°-Lat2) = N + (1-Q)·hav(Bearing)
    where N = hav(Lat1 - (90°-Dist/60))
               P = hav(Lat1 + (90°-Dist/60))
               Q = N + P
    hav(Diff) = (hav(Dist/60) - N) / (1-Q)
    where N = hav(Lat2 - Lat1)
               P = hav(Lat2 + Lat1)
               Q = N + P
    Long2 = Long1 + Diff
    Note that N, P and Q are different in the two formulas. As hav(x) = hav(-x) the longitude difference could be either positive or negative, depending on the bearing. I have checked the formulas for only one case (Lat1=37°, Long1=0°, Bearing=15°, Dist=600'; resulting in Lat2=46°36.3', Long2=3°43.9', with 5-figure haversines) so there may be cases where they do not work. 
    Lars
       
    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