A principal meridian is a
meridian
Meridian or a meridian line (from Latin ''meridies'' via Old French ''meridiane'', meaning “midday”) may refer to
Science
* Meridian (astronomy), imaginary circle in a plane perpendicular to the planes of the celestial equator and horizon
* ...
used for survey control in a large region.
Canada
The
Dominion Land Survey
The Dominion Land Survey (DLS; french: links=no, arpentage des terres fédérales, ATF) is the method used to divide most of Western Canada into one-square-mile (2.6 km2) sections for agricultural and other purposes. It is based on the layout ...
of
Western Canada
Western Canada, also referred to as the Western provinces, Canadian West or the Western provinces of Canada, and commonly known within Canada as the West, is a Canadian region that includes the four western provinces just north of the Canada ...
took its origin at the First (or Principal) Meridian, located at 97°27′28.41″ west of
Greenwich
Greenwich ( , ,) is a town in south-east London, England, within the ceremonial county of Greater London. It is situated east-southeast of Charing Cross.
Greenwich is notable for its maritime history and for giving its name to the Greenwich ...
, just west of
Winnipeg, Manitoba
Winnipeg () is the capital and largest city of the province of Manitoba in Canada. It is centred on the confluence of the Red and Assiniboine rivers, near the longitudinal centre of North America. , Winnipeg had a city population of 749,6 ...
. This line is exactly ten miles west of the Red River at the Canada–United States border.
Six other meridians were designated at four-degree intervals westward, with the seventh located in British Columbia; the second and fourth meridians form the general eastern border and the western border of
Saskatchewan
Saskatchewan ( ; ) is a Provinces and territories of Canada, province in Western Canada, western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on t ...
.
United States
In the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
Public Land Survey System
The Public Land Survey System (PLSS) is the surveying method developed and used in the United States to plat, or divide, real property for sale and settling. Also known as the Rectangular Survey System, it was created by the Land Ordinance of 1 ...
, a principal meridian is the principal north-south line used for survey control in a large region, and which divides townships between east and west. The meridian meets its corresponding
baseline at the point of origin, or
initial point
In surveying, an initial point is a datum (a specific point on the surface of the earth) that marks the beginning point for a cadastral survey. The initial point establishes a local geographic coordinate system for the surveys that refer to that ...
, for the land survey. For example, the
Mount Diablo Meridian, used for surveys in California and Nevada, runs north-south through the summit of
Mount Diablo
Mount Diablo is a mountain of the Diablo Range, in Contra Costa County, California, Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton, California, Clayton and northeast of Danville, Califo ...
.
Often, meridians are marked with roads, such as the Meridian Avenue in
San Jose, California
San Jose, officially San José (; ; ), is a major city in the U.S. state of California that is the cultural, financial, and political center of Silicon Valley and largest city in Northern California by both population and area. With a 2020 popul ...
, Meridian Road in
Vacaville, California
Vacaville is a city located in Solano County in Northern California. Sitting approximately from Sacramento and from San Francisco, it is within the Sacramento Valley. As of the 2020 census, Vacaville had a population of 102,386, making it ...
, both on the
Mount Diablo Meridian, Meridian Road in
Wichita, Kansas
Wichita ( ) is the largest city in the U.S. state of Kansas and the county seat of Sedgwick County, Kansas, Sedgwick County. As of the 2020 United States census, 2020 census, the population of the city was 397,532. The Wichita metro area had ...
on the Sixth Principal Meridian, and Meridian Avenue in several western Washington counties generally following the Willamette Meridian. Baseline Road or Base Line Street extends for about from
Highland, California
Highland (and neighboring "East Highlands") is a city in San Bernardino County, California, United States. The population of the city was 53,104 as of the 2010 census, up from 44,605 at the 2000 census. The term ''Highland'' also refers to a geo ...
east of San Bernardino to
La Verne, California
La Verne is a city in Los Angeles County, California, United States. The population was 31,063 at the 2010 census, down from 31,638 at the 2000 census.
History
The European history of the area dates back to the 1830s when Ygnacio Palomare ...
where it meets Foothill Boulevard.
See also
*
Cardo
A cardo (plural ''cardines'') was a north–south street in Ancient Roman cities and military camps as an integral component of city planning. The cardo maximus, or most often the ''cardo'', was the main or central north–south-oriented street ...
*
Baseline (surveying)
In surveying, a baseline is a line between two points on the earth's surface and the direction and distance between them. In a triangulation network, at least one baseline between two stations needs to be measured to calculate the size of the ...
*
External links
The Principal Meridian Project (US)History of the Rectangular Survey SystemNote: this is a large file, approximately 46MB. Searchable PDF prepared by the author, C. A. White.
Surveying
Meridians (geography)
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