Parallels that are parallel to the equatorial plane extending in the east-west direction of circular lines on the (idealized) surface with a constant φ latitude . In the navigation teach the latitude is fachsprachlich parallel of latitude called. The counterpart is the longitude .
While the width circles vertically extending length circles all great circles are, the width of circuits are generally small circles - up to the equator, which as width 0 ° northern and southern latitude the earth in a northern and southern hemisphere divided. Other special parallels are the tropics and the polar circles, which acquire their importance for the position of the sun in the course of the seasons through the inclination of the ecliptic . The definition of the climatic zones also relates to certain parallels.
The distance between two parallels with a latitude difference of one degree is on average approximately 111 km, but is smaller than in the extreme northern and southern latitudes due to the flattening of the earth near the equator. Calculating the length of the circles of latitude as 2 π R · cos φ with a constant earth radius R would have a similar error . Determining the exact distance between two circles of latitude is the task of the degree measurement . With their help, the exact shape of the earth figure can be determined.
- 90 degrees north: Geographic north pole , circle reduced to the point
- 66.57 degrees North: Arctic Circle
- 23.43 degrees North: Northern Tropic , Tropic of Cancer
- 0 degrees: equator , Latitude 0, only the parallel of the same great circle is
- 23.43 degrees south: Tropic of the Tropic of Capricorn , Tropic of Capricorn
- 66.57 degrees south: Antarctic Arctic Circle
- 90 degrees south: Geographic south pole , circle reduced to the point
Parallels as borders
- 49 degrees north: Part of the border between Canada (N) and the United States (S)
- 45 degrees north: border between Canada (N) and Vermont (S), border between Montana (N) and Wyoming (S)
- 42 degrees north: Oregon (N) and California (S) border, part of the New York (N) and Pennsylvania (S) border
- 41 degrees north: Part of the border between Wyoming and Nebraska (N) on the one hand and Colorado and Utah (S) on the other
- 40 degrees north: border between Nebraska (N) and Kansas (S)
- 39.7 degrees north: Eastern part of the historical border between the states with a ban on slavery in the north of the United States and the slave-holding states in the south ( Mason-Dixon line as the border east of the Mississippi)
- 38 degrees north:
- 37 degrees north: border between Utah, Colorado and Kansas (N) and Arizona , New Mexico and Oklahoma (S)
- 36.5 degrees north: Western part of the historical border between the states with a ban on slavery in the north of the United States and the slave-holding states in the south (border west of the Mississippi according to the Missouri Compromise )
- 35 degrees north: border between Tennessee (N) and Mississippi , Alabama and Georgia (S)
- 32 degrees North: Part of the border between New Mexico (N) and Texas (S)
- 22 degrees north: part of the border between Egypt (N) and Sudan (S)
- 17 degrees north: border between North Vietnam (N) and South Vietnam (S) from 1954 to 1976
- 26 degrees south: part of the border between Northern Territory and Queensland (N) and South Australia (S)
- Ferdinand Mayer : Diercke World Atlas. (185th edition.), 1st edition of the new edition. Westermann, Braunschweig 1974, ISBN 3-14-100500-1 .
- Ferdinand Mayer: Diercke World Atlas. (185th edition.), 1st edition of the new edition. Westermann, Braunschweig 1974, ISBN 3-14-100500-1 .