surveying Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Plane (mathematics), two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of Point (geom ...

, a baseline is generally a line between two points on the Earth's surface and the direction and/or distance between them. In a triangulation network, at least one distance between two stations needs to be measured to calculate the size of the triangles by

trigonometry Trigonometry () is a branch of mathematics concerned with relationships between angles and side lengths of triangles. In particular, the trigonometric functions relate the angles of a right triangle with ratios of its side lengths. The fiel ...

. In relative Global Navigation Satellite System (GNSS) surveying, a baseline is the line between two GNSS receivers to determine the 3D coordinate difference.

United States

In the United States Public Land Survey System, a baseline is specifically the principal east-west line (i.e., a parallel) upon which all rectangular surveys in a defined area are based. The baseline meets its corresponding principal meridian (north-south line) at the point of origin, or '' initial point'', for the land survey. For example, the baseline for

Nebraska Nebraska ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Ka ...

and

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

is shared as the border for both states, at the 40th parallel north. More specifically a baseline may be the line that divides a

survey township A survey township, sometimes called a Congressional township or just township, as used by the United States Public Land Survey System and by Canada's Dominion Land Survey is a nominally-square area of land that is nominally six survey miles (a ...

between north and south.

"Baseline Road"

Many communities in the United States have roads that run along survey baselines, many of which are named to reflect that fact. Some examples: * In Little Rock,

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

, Baseline Road follows the baseline used by surveyors of the

Louisiana Purchase The Louisiana Purchase () was the acquisition of the Louisiana (New France), territory of Louisiana by the United States from the French First Republic in 1803. This consisted of most of the land in the Mississippi River#Watershed, Mississipp ...

. * In

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

, Baseline Road in Boulder marks the 40th parallel, or the western extension of the Kansas-Nebraska boundary, which is also the boundary between Adams and Weld counties. * In

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

, the baseline near the Phoenix metro area is marked by Baseline Road. * In Southern California, from Highland to San Dimas, the baseline is marked by Baseline Road. * In Michigan, the baseline for the Michigan Survey forms the boundary between the second and third tiers of counties and in many portions, discontinuous segments of road along the baseline are known as " Baseline Road." 8 Mile Road in the

Detroit Detroit ( , ) is the List of municipalities in Michigan, most populous city in the U.S. state of Michigan. It is situated on the bank of the Detroit River across from Windsor, Ontario. It had a population of 639,111 at the 2020 United State ...

area runs along the

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

Baseline and was formerly known as "Baseline Road." * Baseline Road in Hillsboro, Oregon, generally follows the Willamette Baseline which intersects the Willamette Meridian at the Willamette Stone State Park. * Base Line Road in Roseville California, was known as "Base Line Road" until the City (incorrectly at the time) named the section of road within their incorporated area, "Baseline Road". They petitioned the County for a name change, and the spelling was changed effective 11/20/17

Canada

In Canadian land surveying, a base line is one of the many principal east-west lines that correspond to four tiers of townships (two tiers north and two south). The base lines are about apart, with the first base line at the 49th parallel, the western Canada–US border. It is, therefore equivalent to the ''standard parallel'' in the US system.

Ontario

In Ontario, a baseline forms a straight line parallel a geographical feature (mostly a lake, especially

Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York (state), New York. The Canada–United Sta ...

Lake Erie Lake Erie ( ) is the fourth-largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and also has the shortest avera ...

) that serves as a reference line for surveying a grid of property lots. The result of this surveying is the concession road and sideline system in use today. Many prominent Ontario baselines lie on the surveyed boundaries of land treaties signed with

First Nations First nations are indigenous settlers or bands. First Nations, first nations, or first peoples may also refer to: Indigenous groups *List of Indigenous peoples *First Nations in Canada, Indigenous peoples of Canada who are neither Inuit nor Mé ...

peoples. For example, several baselines in Waterloo Region and Brant County (including Wilmot Line, Brant-Oxford Road, and Indian Line) follow the borders of the Haldimant Tract land grant to the Six Nations confederacy, leading to the patchwork road and lot network, surveyed parallel to the western edge of the tract, which can be seen in this area to this day. Jones Baseline which runs through Wellington County and Halton Region follows the original survey route marked by Augustus Jones after the Between the Lakes Purchase in 1792.

External links

The Principal Meridian Project (US)
* ttps://web.archive.org/web/20081010234903/http://www.blm.gov/cadastral/Manual/pdffiles/histrect.pdf History of the Rectangular Survey SystemNote: This is a large file, approximately 46MB. Searchable PDF prepared by the author, C. A. White.

References