principal meridian


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principal meridian

One of the imaginary lines running north and south,used as references for the public land survey system. There are 37 principal meridians in the United States. Each one has a name, and the names are used to distinguish the various surveys that eventually made up the public land survey system.

References in periodicals archive ?
00D will be the principal meridian with the higher absolute BVP, so as that is less than 3.
Therefore, the user must be aware of the importance of considering both principal meridian powers.
Dorsher concluded that, The marked degree of correspondence noted in this qualitative study between the distributions of the anatomically derived myofascial meridians to those of acupuncture Principal Meridians is unlikely to be coincidental'.
Corneal factors include the difference in the radii of curvature of the principal meridians.
Astigmatism is also classified on the relationship between the two principal meridians as regular (when two principal meridians are perpendicular to each other) and irregular (when the two principal meridians are not perpendicular to each other).
Astigmatism was classified on the basis of relationship between the two principal meridians as regular (when two principal meridians are perpendicular to each other) and irregular (when the two principal meridians are not perpendicular to each other).
The translation is "the northwest quarter of the southeast quarter of section 14 in township 6 north and range 11 west of the 6th Principal Meridian.
This well was drilled in Section 23-14 Township 152, Range 101 West, 5th Principal Meridian and immediately east (less than 2,500') in Sections 24 and 13, the company owns mineral rights which have been leased to Oasis Petroleum.
Some practitioners believe that steepening the Back Optic Zone Radius (BOZR), to a new value a third, or halfway, between the principal meridians, will create a more stable fitting lens, however, research tends to suggest that this is not a creditable method.
Patients who have difference in principal meridians from keratometer readings greater than 0.
Notes: A tract of land in the County Clerk~s Subdivision of the North Half of the Southeast Quarter of the Southeast Quarter of Section 20, Township 26 North, Range 12 West of the Second Principal Meridian, in Iroquois County, Illinois, described as follows: Beginning at the Northwest corner of Lot 8 of the County Clerk~s Subdivision of the North Half of the Southeast Quarter of the Southeast Quarter of Section 20, Township 26 North, Range 12 West of the Second Principal Meridian, Iroquois County, Illinois, as recorded in Plat Book E, page 94 of the Iroquois County Records thence Northerly on the West line of said Lot 8 extended 140.
Pre-regs should, if using a keratometer, ensure they find the principal meridians, but also ensure that they know the theory on both one and two-step design keratometers.

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