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Paul Hirose is always reliable, helpful, and to-the point.

He responded to my recent mailing as follows

>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:
>
>http://www.dnr.state.mo.us/geology/lndsrv/lsfaq.htm
>
>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monuments have long since been replaced by more modern and precise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.

Thank you, Paul, that's useful information, and I will follow it up.

>> 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?
>http://lewisclark.geog.missouri.edu/campsintro.shtml
>
>They plot the sites on modern topo maps with the old river course
>added. For example,
>
>http://lewisclark.geog.missouri.edu/campsites/1804/may30camp.shtml
>
>(The red lines are the public land survey; note the 1-mile squares.)

Yes, I have seen some of these. In fact some such mapping (or very similar)
is provided as inserts on the Harlan and Denny maps, for some, but not all,
of the campsites.

>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 hadn't realised that information was there, at all, and will try it out,
as soon as I get into cheap-rate on my phone (here, we have to pay for our
local calls, and my modem's VERY slow!).

>I verified that by measuring the coordinates of the May 30/31 camp
>site and entering them into Topozone's coordinate entry page:
>
>http://www.topozone.com/viewmaps.asp
>
>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.
>
>http://www.topozone.com/map.asp?z=15&e=601110&n=4279640&datum=NAD83&u=4

Isn't this list a powerful means of information exchange, with members such
as Paul Hirose aboard it?

============================

By the way, I forgot to mention, in my description of the Harlan and Denny
"Atlas of Lewis and Clark in Missouri", that as a bonus it contains in
pockets two large fold-up poster-size maps of Missouri (about 28 x 26
inches), one showing their outward journey, and the other their return.

George.




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contact George Huxtable by email at george@huxtable.u-net.com, by phone at
01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
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