I'm not exactly sure what category to place this discussion. I need some help defining a term. Let's define "North". Here are some terms I hear thrown about: "True North", "Geodetic North", "Due North". What do these terms really mean? I want to be sure I use these terms correctly.

Find Similar Content by Clicking These Tags ☟
Subject Tags: Geodesy, Geodetic, North, Plane, Surveying

This Content Originally Published to Land Surveyors United Network

Views: 731

☇ Reply to this

Replies to This Discussion

The word north is related to the Old High German nord, both descending from the Proto-Indo-European unit ner-, meaning "down" (or "under"). (Presumably a natural primitive description of its concept is "to the left of the rising sun".)

Latin borealis is from Greek boreas "north wind, north", in mythology (according to Ovid) personified as the son of the river-god Strymon, and father of Calais and Zetesseptentrionalis is fromseptentriones, "the seven plow oxen", a name of Ursa Maior. Greek arktikos "northern" is named for the same constellation (c.f. Arctic).

Other languages have sometimes more interesting derivations. For example, in Lezgian kefer can mean both 'disbelief' and 'north', since north of Muslim Lezgians there are areas inhabited by non-Muslim (until recently) Caucasian peoples, such as Avars and Chechens; as well as pagan Turkic peoples. In many languages of Mesoamerica, 'north' also means 'up'.

Magnetic north and declination

Magnetic north is of interest because it is the direction indicated as north on a properly functioning (but uncorrected) magnetic compass. The difference between it and true north is called the magnetic declination (or simply the declination where the context is clear). For many purposes and physical circumstances, the error in direction that results from ignoring the distinction is tolerable; in others a mental or instrument compensation, based on assumed knowledge of the applicable declination, can solve all the problems. But simple generalizations on the subject should be treated as unsound, and as likely to reflect popular misconceptions about terrestrial magnetism.

Maps intended for usage in orienteering by compass will clearly indicate the local declination for easy correction to true north. Maps may also indicate grid north, which is a navigational term referring to the direction northwards along the grid lines of a map projection.

Roles of north as prime direction

The visible rotation of the night sky around the visible celestial pole provides a vivid metaphor of that direction corresponding to up. Thus the choice of the north as corresponding to up in the northern hemisphere, or of south in that role in the southern, is, prior to world-wide communication, anything but an arbitrary one. On the contrary, it is of interest that Chinese and Islamic culture even considered south as the proper top end for maps.

In Western culture:

  • Maps tend to be drawn for viewing with either true north or magnetic north at the top
  • Globes of the earth have the North Pole at the top, or if the Earth's axis is represented as inclined from vertical (normally by the angle it has relative to the axis of the Earth's orbit), in the top half.
  • Maps are usually labelled to indicate which direction on the map corresponds to a direction on the earth,
    • usually with a single arrow oriented to the map's representation of true north,
    • occasionally with a single arrow oriented to the map's representation of magnetic north, or two arrows oriented to true and magnetic north respectively,
    • occasionally with a compass rose, but if so, usually on a map with north at the top and usually with north decorated more prominently than any other compass point.
  • Up is a metaphor for north. The notion that north should always be up and east at the right was established by the Greek astronomer Ptolemy. The historian Daniel Boorstin suggests that perhaps this was because the better-known places in his world were in the northern hemisphere, and on a flat map these were most convenient for study if they were in the upper right-hand corner.

Being the "default" direction on the compass, North is referred to frequently in Western popular culture. Some examples include:

  • The phrase "north of X" is often used to mean "more than X" or "greater than X", i.e. "The world population is north of 6 billion people."

In my opinion, the difference between the three terms are as follows:

  1. True North is simply the direction towards the north pole point. This simply means that in a given survey project, how small it is, there are infinite number of true north direction lines.
  2. Magnetic North is the north direction provided by the compass as it is magnetic in nature. This direction is influenced by the magnetic field in a locality. This also simply means that in a given survey project, how small it is, there are infinite number of magnetic north direction lines.
  3. Grid North is the north direction derived through map projection process. It is a direction used to effect map homogeneity in a flat/2D domain. Grid North direction is contained within specified zone width to minimize distortion.
  4. Geodetic North is an instantaneous north direction of a particular geographic point location. Grid north is parallel to geodetic north direction within same zone. The amount of rotation between true and geodetic north directions at a particular geographic point is termed as convergence angle. This means that in a given project within a single zone, there is only one grid direction line.
  5. Due north is simply a direction towards the adopted north direction line be it arbitrary (assumed or local), magnetic, true, or grid.

Hope this helps.

nice work arnel! i'd go with Arnel's version.....i believe Justin was just trying to help, but Arnel is definitely at the top of his game!  sorry son...nice try

What is "North"?  Almost certainly everybody knows which way is North, or do they?  The answer is that everybody knows what North is and it's relationship with South, East, and West.  The problem is that we all are not coplanar in our reference system.  Does the Sun not rise in the East? Of course. That is the problem with the relative frame of thought when applying direction in a relative way. Is China East or West of the United States?  Well, it is both!  My point is that North only exists in the human mind as a point of reference for a geospatial relationship with other entities exist on Earth.  EARTH!  Which way is North when orbiting the Earth as an astronaut would do?  My guess is that the astronaut would necessarily focus on what is North on Earth, even though he or she is not on Earth.  Imagine that an astronaut ventures so far away that Earth is no longer visible.  Now, which way is North?  Can one be North of the Earth?

Terrestrial reference systems on Earth in a professional sense are commonly called datums.  Within each datum, there are constraining elements that define its parameters as a terrestrial reference system.  North in one datum is not necessarily the same North in another. Although the "Norths" may be generally sharing the polarity of the Earth as a similar point of reference, no datum can be proven to be better oriented than another.  It is all relative to what the information is being used for and at what scale.  The applied value of North as a singularity is worthless out of context.  There is no North unless you call it such.

RSS

Global Trade organization for Professional Land Surveyors and Geospatial Pros. Frictionless GeoCollaboration Surveying Forum and Groups

Surveyor Hubs and Tags

Surveyor Community Hubs For World Regions

Surveying Hubs For US States

Social Support For Equipment

Surveying Photos by Tag

Surveying Videos by Tag


Share on Tumblr
+ Surveyor Sharer

Drag Button to bookmark bar and view submitted links here.Will soon be moved to a directory

What You Missed

Profile IconOmar Rubio, Issahaku Ibrahim and Nikos Argyropoulos joined Land Surveyors United :
8 hours ago
JAmie Gillis commented on Kevin Gaunt, L.S.I.T.'s photo
Land Survey Media Thumbnail

Cold swim Surveying

"Hi Kevin, I'm working on a recruitment campaign to educate high school students about career…"
8 hours ago
Profile IconMatthew M Filus, Soviet B Mutamba, Jerry and 1 more were featured
10 hours ago
Matthew M Filus's photo was featured

SURVEYOR Mural Close-Up

Fermentation Fest - Farm Art/Dtour Exhibit Near Reedsburg, WICREATED BY: JOHN MILLER, MADISON, WIIN…
11 hours ago
Surveying Jobber's video was featured

Traverse by Bearing and Distance

Watch this insightful tutorial on Traverse by Bearing and Distance for land surveying
11 hours ago
AxeMen Site Prep's video was featured

GIS Video Tutorial #1

Tutorial for getting started with GIS
11 hours ago
Profile IconThere are 6403 photos on Land Surveyors United :
11 hours ago
Profile IconThere are 7976 members on Land Surveyors United :
11 hours ago
Regis Kapuyah joined LSU Justin's group
Land Survey Media Thumbnail

Bootstrap Company Website Template

This group is for discussions related to customizing the…See More
13 hours ago
Regis Kapuyah joined ePalmetto's group
Land Survey Media Thumbnail

Zimbabwe Surveyors

Zimbabwe Surveyors Group is a support forum for surveyors who work in the African country of…See More
15 hours ago
Regis Kapuyah promoted ePalmetto's group Zimbabwe Surveyors
15 hours ago
Aman ullah Nasaree replied to charlie-jm's discussion best software to used in surveying
"There are many software but AutoCAD Civil 3D is the best "
16 hours ago
Aman ullah Nasaree posted a photo

Nasiri

Qarabagh, Kabul, Afghanistan
17 hours ago
Soviet B Mutamba replied to Soviet B Mutamba's discussion Certification of Geo-Information Practitioners
"Hie Justin, thank you for your reply. Legislation on Surveying and Geomatics/GeoSpatial disciplines…"
19 hours ago
Soviet B Mutamba posted a photo

Kariba 2013 (Lease Survey)

Soviet Standing at one of the Trig beacons on the Zimbabwean side in Kariba close to the…
20 hours ago
Michael Papenhagen's blog post was featured
yesterday
Jerry's discussion was featured

Terramodel software

Are there any members of this forum that are willing to detail their experience with Terramodel…See More
yesterday
LSU Justin's photo was featured

Quiz:Total Station Parts

Name the Parts of This Total Station in the comments below
yesterday
LSU Justin's video was featured

Casio Graphical Calculators: Basics (fx-9860GII)

This video introduces you to the basic operations on a Casio Graphical Calculator, with further videos to show other topics such as drawing graphs and statistical calculations. I am using an fx-9860GII, but all Casio graphical calculators work in…
yesterday
Soviet B Mutamba's discussion was featured

Certification of Geo-Information Practitioners

Hie, my name is Soviet a Land Surveyor from Zimbabwe. I am currently writing an article on the…See More
yesterday

Take This Page With You

follow us in feedly

Take this Page With You

QR Code for This Page: What is this?

Surveyor Support

Dedicated to the Memory of Skip Farrow (1953-2015)

AFGHANISTAN SURVEYORS ALBANIA SURVEYORS ALGERIA SURVEYORS AMERICAN SAMOA SURVEYORS ANDORRA SURVEYORS
ANGOLA SURVEYORS ANGUILLA SURVEYORS ANTIGUA & BARBUDA SURVEYORS ARGENTINA SURVEYORS ARMENIA SURVEYORS
ARUBA SURVEYORS AUSTRALIA SURVEYORS AUSTRIA SURVEYORS AZERBAIJAN SURVEYORS BAHAMAS SURVEYORS
BAHRAIN SURVEYORS BANGLADESH SURVEYORS BARBADOS SURVEYORS BELARUS SURVEYORS BELGIUM SURVEYORS
BELIZE SURVEYORS BENIN SURVEYORS BERMUDA SURVEYORS BHUTAN SURVEYORS BOLIVIA SURVEYORS
BOSNIA & HERZEGOWINA SURVEYORS BOTSWANA SURVEYORS BRAZIL SURVEYORS BRITISH INDIAN OCEAN TERRITORY SURVEYORS
BRUNEI DARUSSALAM SURVEYORS BULGARIA SURVEYORS BURKINA FASO SURVEYORS BURUNDI SURVEYORS CAMBODIA SURVEYORS
CAMEROON SURVEYORS CANADA SURVEYORS CAPE VERDE SURVEYORS CAYMAN ISLANDS SURVEYORS CENTRAL AFRICAN REPUBLIC SURVEYORS
CHAD SURVEYORS CHILE SURVEYORS CHINA SURVEYORS COLOMBIA SURVEYORS COMOROS SURVEYORS
CONGO SURVEYORS DEMOCRATIC REPUBLIC OF THE CONGO SURVEYORS COOK ISLANDS SURVEYORS COSTA RICA SURVEYORS COTE D'IVOIRE SURVEYORS
CROATIA SURVEYORS CUBA SURVEYORS CURACAO SURVEYORS CYPRUS SURVEYORS CZECH REPUBLIC SURVEYORS
DENMARK SURVEYORS DJIBOUTI SURVEYORS DOMINICA SURVEYORS DOMINICAN REPUBLIC SURVEYORS ECUADOR SURVEYORS
EGYPT SURVEYORS EL SALVADOR SURVEYORS EQUATORIAL GUINEA SURVEYORS ERITREA SURVEYORS ESTONIA SURVEYORS
ETHIOPIA SURVEYORS EUROPEAN UNION SURVEYORS FAROE ISLANDS SURVEYORS FIJI SURVEYORS FINLAND SURVEYORS
FRANCE SURVEYORS FRENCH GUIANA SURVEYORS FRENCH POLYNESIA SURVEYORS GABON SURVEYORS GAMBIA SURVEYORS
GEORGIA SURVEYORS GERMANY SURVEYORS GHANA SURVEYORS GIBRALTAR SURVEYORS GREECE SURVEYORS
GREENLAND SURVEYORS GRENADA SURVEYORS GUADELOUPE SURVEYORS GUAM SURVEYORS GUATEMALA SURVEYORS
GUERNSEY SURVEYORS GUINEA SURVEYORS GUINEA-BISSAU SURVEYORS GUYANA SURVEYORS HAITI SURVEYORS
HOLY SEE SURVEYORS HONDURAS SURVEYORS HONG KONG SURVEYORS HUNGARY SURVEYORS ICELAND SURVEYORS
INDIA SURVEYORS INDONESIA SURVEYORS IRAN SURVEYORS IRAQ SURVEYORS IRELAND SURVEYORS
ISLE OF MAN SURVEYORS ISRAEL SURVEYORS ITALY SURVEYORS JAMAICA SURVEYORS JAPAN SURVEYORS
JERSEY SURVEYORS JORDAN SURVEYORS KAZAKHSTAN SURVEYORS KENYA SURVEYORS KIRIBATI SURVEYORS
KOREA SURVEYORS KOREA REPUBLIC OF SURVEYORS KUWAIT SURVEYORS KYRGYZSTAN SURVEYORS LAO PEOPLE'S DEMOCRATIC REPUBLIC SURVEYORS
LATVIA SURVEYORS LEBANON SURVEYORS LESOTHO SURVEYORS LIBERIA SURVEYORS LIBYAN ARAB JAMAHIRIYA SURVEYORS
LIECHTENSTEIN SURVEYORS LITHUANIA SURVEYORS LUXEMBOURG SURVEYORS MACAU SURVEYORS MACEDONIA SURVEYORS
MADAGASCAR SURVEYORS MALAWI SURVEYORS MALAYSIA SURVEYORS MALDIVES SURVEYORS MALI SURVEYORS
MALTA SURVEYORS MARSHALL ISLANDS SURVEYORS MARTINIQUE SURVEYORS MAURITANIA SURVEYORS MAURITIUS SURVEYORS
MAYOTTE SURVEYORS MEXICO SURVEYORS MICRONESIA SURVEYORS MOLDOVA SURVEYORS MONACO SURVEYORS
MONGOLIA SURVEYORS MONTENEGRO SURVEYORS MONTSERRAT SURVEYORS MOROCCO SURVEYORS MOZAMBIQUE SURVEYORS
MYANMAR SURVEYORS NAMIBIA SURVEYORS NAURU SURVEYORS NEPAL SURVEYORS NETHERLANDS SURVEYORS
NEW CALEDONIA SURVEYORS NEW ZEALAND SURVEYORS NICARAGUA SURVEYORS NIGER SURVEYORS NIGERIA SURVEYORS
NIUE SURVEYORS NON-SPEC ASIA PAS LOCATION SURVEYORS NORFOLK ISLAND SURVEYORS NORTHERN MARIANA ISLANDS SURVEYORS NORWAY SURVEYORS
OMAN SURVEYORS PAKISTAN SURVEYORS PALAU SURVEYORS PALESTINIAN TERRITORY OCCUPIED SURVEYORS PANAMA SURVEYORS
PAPUA NEW GUINEA SURVEYORS PARAGUAY SURVEYORS PERU SURVEYORS PHILIPPINES SURVEYORS POLAND SURVEYORS
PORTUGAL SURVEYORS PUERTO RICO SURVEYORS QATAR SURVEYORS RESERVED SURVEYORS REUNION SURVEYORS
ROMANIA SURVEYORS RUSSIAN FEDERATION SURVEYORS RWANDA SURVEYORS SAINT KITTS & NEVIS SURVEYORS SAINT LUCIA SURVEYORS
SAINT MARTIN SURVEYORS SAINT VINCENT & THE GRENADINES SURVEYORS SAMOA SURVEYORS SAN MARINO SURVEYORS SAO TOME & PRINCIPE SURVEYORS
SAUDI ARABIA SURVEYORS SENEGAL SURVEYORS SERBIA SURVEYORS SEYCHELLES SURVEYORS SIERRA LEONE SURVEYORS
SINGAPORE SURVEYORS SINT MAARTEN SURVEYORS SLOVAKIA (SLOVAK REPUBLIC) SURVEYORS SLOVENIA SURVEYORS SOLOMON ISLANDS SURVEYORS
SOMALIA SURVEYORS SOUTH AFRICA SURVEYORS SOUTH SUDAN SURVEYORS SPAIN SURVEYORS SRI LANKA SURVEYORS
ST. PIERRE AND MIQUELON SURVEYORS SUDAN SURVEYORS SURINAME SURVEYORS SWAZILAND SURVEYORS SWEDEN SURVEYORS
SWITZERLAND SURVEYORS SYRIAN ARAB REPUBLIC SURVEYORS TAIWAN; REPUBLIC OF CHINA (ROC) SURVEYORS TAJIKISTAN SURVEYORS TANZANIA UNITED REPUBLIC OF SURVEYORS
THAILAND SURVEYORS TIMOR-LESTE SURVEYORS TOGO SURVEYORS TOKELAU SURVEYORS TONGA SURVEYORS
TRINIDAD AND TOBAGO SURVEYORS TUNISIA SURVEYORS TURKEY SURVEYORS TURKMENISTAN SURVEYORS TURKS AND CAICOS ISLANDS SURVEYORS
TUVALU SURVEYORS UGANDA SURVEYORS UKRAINE SURVEYORS UNITED ARAB EMIRATES SURVEYORS UNITED KINGDOM SURVEYORS
UNITED STATES SURVEYORS URUGUAY SURVEYORS UZBEKISTAN SURVEYORS VANUATU SURVEYORS VENEZUELA SURVEYORS
VIET NAM SURVEYORS VIRGIN ISLANDS (BRITISH) SURVEYORS VIRGIN ISLANDS (U.S.) SURVEYORS WALLIS AND FUTUNA ISLANDS SURVEYORS YEMEN SURVEYORS
ZAMBIA SURVEYORS ZIMBABWE SURVEYORS SURVEYORS

© 2015   © Created by Land Surveyors United

Badges  |  Contact LSU  |  Privacy Policy  |  Terms of Service

Live Support