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: Lewis and Clark Missouri Atlas
    From: Paul Hirose
    Date: 2003 Dec 21, 21:47 -0800

    George Huxtable wrote:
    > unavailable until the telegraph arrived. Presumably, modern coordinates for
    > those old maps have now now been obtained by correlating identifiable and
    > unchanging features (so, not the river-course) with modern maps on a known
    The Lewis & Clark atlas makers probably tied the old records to modern
    mapping by means of the section corners the GLO established way back
    when. This page from the Missouri state survey office explains better
    than I could:
    Their description is true for just about all the states outside the
    original 13 colonies. For example, the section corners in my portion
    of California were marked in the late 1850s, though the original
    monuments have long since been replaced by more modern and precise
    ones set in exactly the same locations. After they're approved by
    Washington, the monuments in a public land survey can't be moved.
    > Although the maps are all stated to be on a modern projection (Universal
    > Transverse Mercator, zone 15), no grid squares are shown, not even any
    > marks in the margins, for UTM or lat/long or anything else. There is just
    > no way to relate positions in this atlas to positions on any other mapping,
    George, have you seen the online Lewis & Clark campsite maps?
    They plot the sites on modern topo maps with the old river course
    added. For example,
    (The red lines are the public land survey; note the 1-mile squares.)
    The "Interactive Map Server" at the same Web site is not so detailed,
    but more flexible. You can zoom in or out, pan around, turn map layers
    on or off, and read out coordinates. Your browser displays the numbers
    as you move the mouse pointer over the map. (At least, Netscape does,
    down in the status line.) These are UTM easting and northing in the
    NAD83/WGS84 datum.
    I verified that by measuring the coordinates of the May 30/31 camp
    site and entering them into Topozone's coordinate entry page:
    They produced a map of the site as it is today. Note how well the red
    crosshair's location matches the red star on the "campsites" map.

    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