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Northings & Eastings

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The Northing and Easting nomenclature is specific to surveying and Civil Engineering students, but it won’t hurt the drafting students to become familiar with it, too.

A long time ago, even before N’Sync, Donny Osmond, disco, the Beatles, and Elvis, a group of people gathered together to develop a system of surveying and measuring the State of Oregon.

What these people created is called the State Plane Coordinate System (SPCS). Imagine this as a giant X-Y grid placed on top of a map of Oregon. This grid provides a known reference location for every mountain, river, county, city, block, street , etc., and every inch of Oregon.

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Please excuse the rather crude drawing of Oregon.

 

The numbers associated with Northings and Eastings are equivalent to the distance, in feet, from a known location. Actually, the true SPCS was created in meters, but this can be quickly converted to feet for convenience of calculation. And you certainly are capable of those calculations by this point, aren’t you?

You might ask,

Where is the origin of the SPCS?

Since they did not wish to use negative numbers in the SPCS, the origin was placed somewhere Southwest of Brookings, out in the Pacific Ocean, approximately in the middle of the tuna and dolphin playground. This was the equivalent of placing the State of Oregon in Quadrant I of a Cartesian system where the X and Y values will always be positive numbers.

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It should also be noted that the Oregon SPCS is not unique, other states have similar coordinate systems and origin points. And no, there isn’t an Oregon SPCS monument floating on a raft anchored exactly at the origin point of the SPCS somewhere in the Pacific Ocean. That would be silly.

 

If you were to compare the SPCS Northings and Eastings to the Cartesian Coordinate System:

Most commonly, a specific location is denoted as a pair of numbers within parentheses with the Northing value appearing first, then the Easting. See the examples below:

(Northing, Easting)

(4456.3451, 3347.9902)

These numbers indicate that the location is 4456.3451 ft North and 3347.9902 ft East of the origin. As you can see by the number of decimal places, the SPCS strives to achieve a high level of accuracy. The SPCS is the basis for all geodetic surveying activity.

Therefore, when calculating distance between points on a map using Northings and Easting values, the process is similar to calculating the distance between points on a Cartesian system. Just remember when using SPCS,

 

EXAMPLE PROBLEM: Monument A is located on the SPCS at (897788.5678, 11087.7654). Monument B is located at (888579.6733, 231678.9965). What is the distance between these monuments?

First and foremost, do not be frightened by the large numbers. These are just numbers. Keep repeating to yourself, ‘’It’s only numbers, they can’t hurt me, it’s only numbers, they can’t hurt me….’’

Second, use the formula for calculating the distance between two points for the Cartesian system previously described:

Monument A = (y1, x1) = (897788.5678, 11087.7654)

Monument B = (y2, x2) = (888579.6733, 23167.9965).

| Ä x | = | x2 - x1 | = | 23167.9965 - 11087.7654 | = 12080.2311

| Ä y | = | y2 - y1 | = | 888579.6733 - 897788.5678 | = -9208.8945

r = sqrt[| Ä x |² + | Ä y |²]

r = sqrt[ 12080.2311² + -9208.8945² ]

r = sqrt[ 145931983.429 + 84803737.9121 ]

r = sqrt[ 230735721.341 ]

r = 15189.9875 feet or 2.87 miles

 

Engineering and surveying student will learn much more about the SPCS in future surveying classes, probably more than they ever thought they would want to know.

The rest of you should be aware that such as system exists, so don’t sit there with a blank look on your face when someone says Northings, Eastings or the State Plane Coordinate System. Nod your head as though you understand fully. Look interested.

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