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
    Re: Ecef
    From: Lu Abel
    Date: 2001 Jul 24, 8:35 PM

    1.  What are the units of measurement?  I think I could grasp
    1368950/-4603950/4182550 more easily with a unit of measurement.
    2.  I don't necessarily agree that it might make determination of our
    centroid easier. An average in ECEF coordinates would easily give us a
    point in the middle of the earth!   Don't know about you, but I prefer
    sailing to digging :-)
    Lu Abel
    At 10:31 PM 7/24/2001 +0000, you wrote:
    >Earth Centered Earth Fixed Cartesian coordinates.
    >The origin is at the center of the earth. The positive z-axis goes through the
    >N-pole. The positive x-axis goes through the equator and the Greenwich
    >meridian. The y-axis completes the orthogonal system.
    >Roughly speaking, ECEF coordinates are what you get when you use the formula
    >given by  R. van Gent and multiply with the radius of the Earth in meters.
    >   x = R * cos(lat) * cos(long)
    >   y = R * cos(lat) * sin(long)
    >   z = R * sin(lat)
    >Strictly speaking, you must account for the spheroidal shape of the earth.
    >These coordinates are easier to use in computers because all trigonometry
    >becomes algebra. Your GPS reciever uses them internally, astronomers need them
    >for exact topocentric reductions, or surveyors, for instance when they have to
    >transform maps from one datum into another.
    >There goes:
    >Herbert Prinz (from 1368950/-4603950/4182550 ECEF)
    >Dan Allen wrote:
    > >
    > > Just what are ECEF coordinates?  I've never heard of them.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    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 Settings

    Posting 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