Subject: Re: roundup of great circle boundaries in the united states
Date: Oct 08, 2000 @ 17:51
Author: jwahl@qubicle.com (jwahl@...)
Prev    Post in Topic    Next [All Posts]
Prev    Post in Time    Next


I wish you would come up with alternative nomenclature for circular
boundaries since the term "great circle" has particular meaning in
the navigational, mapping and 'global'ly viewed world.

A great circle being roughly described as the line between points
lying on the intersection of a plane which passes through the earth
center and each end point and the earth surface. We see these
things as straight lines and the shortest path between two points.

There are boundaries which are straight, some which follow features
and some which are lines of constant bearing (loxodromes) of which
the east west near parallels of latitude are a mere subset. Anyway
examples of great circles are the easterly bounds of California, at
least by intent if not in fact, the south line of california also is
a
straight line.

Commenting on your #5

--- In BoundaryPoint@egroups.com, michael donner <m@d...> wrote:
>
> 5
> washington dc
> u s naval observatory reserve
> circa 1830
> radius about 2100 feet
> http://www.topozone.com/map.asp?lat=38.9219&lon=-77.0608&s=25&size=s
>
> another tangent
> this observatory is the american counterpart of the one in greenwich
> england for setting time standards & it was used in the 19th
> century as a longitude standard as well in fact it was the position
> of this observatory a few minutes west of the 77th meridian that
> caused many of the longitudinal state lines in the west
> such as those of wyoming & colorado to be similarly offset from
> integral meridians because boundaries used to be routinely
> described & marked in terms of whole degrees west of the naval
> observatory or of the washington meridian as it was also called


I think you will find that the current location of the naval
observatory (also the vice presidents home) at observatory circle is
NOT now where it was when the washington meridian was often
referenced. That original location was somewhere down in 'foggy
bottom' south and possibly west of where the white house is found
today. The observatory was relocated to it's current location in
circa 1893.

http://www.usno.navy.mil/brief_history.shtml

I have not followed through to completion investigation as to what
degree the actual location is known, monumented or recoverable.

Interestingly however there is an "axis" along a meridian very nearly
on the washington meridian formed by the white house on the north,
and the jefferson memorial on the south and containing in order, the
"zero mile stone", a monument whose name I cannot recall which lies
at
the center of the ellipse, and "the jefferson pier". There is a
new book just out about the attempts to establish the washington
meridian by Silvio Bedini, historian emeritus of the Smithsonian. I
had previously found another interesting article with a different
slant on the issue:

http://www.usm.maine.edu/~maps/edney/vaughan.html

I am not sure the official proposal for a meridian at the Jefferson
Pier was ever adopted or used. The description of the original
observatory as being "near the current location of the lincoln
memorial" which is a bit to the west, of this other axis indicates to
me that the functional meridian based on the original naval
observatory was different than these later attempts to create
one at the Jefferson pier. And perhaps neither was effectively used
due to the available technology of the day making it moot.

Yes some state bounds refer to the washington meridian, but it is
not clear sometimes what was actually meant. Examples are that the
east line of CA was defined from greenwich but as I recall the west
line of Nevada was defined relative to washington meridian, possibly
indicating an intent to consider the washington meridian at 77 degees
exact from greenwich but confusing the issue of it's definition and
use elsewhere. Often lines were defined one way in the territorial
boundaries and changed when statehood happened.

Just some fragmentary tidbits... this is my first note on this group.

- jerry wahl

>
> any other boundary circles anyone may be aware of anywhere would
make
> welcome additions
>
> m