dear jerry
welcome & thanxx for these several excellent additions
of course you are right & i am happy to comply
i only meant circle boundaries that are great
not boundaries that are great circles
great circles have always eluded me anyway
so it is good that you have helped me out here
like
people seem to call things great circles that i would only be inclined to
call arcs of great circles
etc
etc
i guess what you are implying also is that all true northsouth boundaries
are great circle boundaries too
but true eastwest ones are not great circle boundaries
or have i still not understood
very glad to have your fragmentary tidbits too
so please keep them coming
i agree available tech of the day did make it moot
as the great disparities among the various offsets indicate
but it is always best to have the truth
& it was interesting besides
m
>
>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=-77.0608=25=s>
>>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>
>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>
>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