We explain what parallels and meridians are and the characteristics of each one. Also, how they are used to determine geographic coordinates and time zones.
What are parallels and meridians?
Parallels and meridians are two types of imaginary lines that segment the globe horizontally and vertically, respectively. With this division, the geographic coordinate system is created, which allows locating any place on the planet based on its longitude and latitude.
- Parallels. They are parallel circles that extend horizontally on the planisphere, maintaining a constant distance from the equator. The equator is the reference parallel, with a latitude of 0°, that divides the Earth into two hemispheres: northern and southern. Other important parallels are the Tropics of Cancer and Capricorn, and the Arctic and Antarctic Circles.
- Meridians. They are vertical semicircles that extend from the north pole to the south pole. The Greenwich Meridian is the reference meridian, with a longitude of 0°, that divides the Earth into two hemispheres: eastern and western. In addition, it is the point from which all the time zones on the planet are calculated.
Parallels are used to calculate latitude (the distance of any point on the planet from the equator) and meridians are used to calculate longitude (the distance of any point on the planet from the Greenwich meridian). From this coordinate system, each place in the world has its own latitude and longitude. For example, Panama City is located at 8° north latitude and 80° west longitude.
Characteristics of parallels and meridians
The parallels and meridians have the following characteristics:
- They are the imaginary horizontal and vertical lines that determine the geographic coordinate system.
- They are used for GPS (global positioning system) and GIS (geographic information systems) navigation.
- The most important parallel is the equator, which divides the planet into the northern and southern hemispheres.
- The most important meridian is the Greenwich meridian, which divides the planet into the eastern and western hemispheres.
- The parallels determine the climatic bands of the planet.
- Meridians are used to determine time zones.
Geographic coordinates
Parallels and meridians are the basis of the geographic coordinate system. These coordinates allow you to identify the location of any point on the Earth's surface.
- Latitude. It is measured in degrees towards north or south. It varies from 0° at the equator to 90° at the poles. Latitude values are expressed in degrees (°), minutes ('), and seconds («).
- Length. It is measured in degrees towards east or west. It varies from 0° on the Greenwich meridian to 180° east and west. Like latitude, it is expressed in degrees, minutes and seconds.
For example, the city of Oslo, capital of Norway, is located at 60° north latitude and 10° east longitude.
Parallels and important meridians
In addition to the equator line, which is equidistant from the poles and represents the largest circumference of the Earth, there are other important parallels:
- He Tropic of Cancer and Tropic of Capricorn. They are located at 23.5° north and 23.5° south, respectively. They mark the limits of the tropical and equatorial zones. They also demarcate the areas of the planet with warmer climates. On the summer solstice, the sun is directly over the Tropics of Cancer and Capricorn at 12 AM.
- Arctic Circle and Antarctic Circle. They are located at 66.5° north and 66.5° south, respectively. They mark the beginning of the regions where the phenomena of the midnight sun (time of year when it never gets dark) and the polar night (time of year when it never gets daylight) occur, during the summer and winter solstices. They approximately determine the beginning of the polar cold zones on the planet.
On the other hand, in addition to the Greenwich meridian, which is the starting point for measuring longitude, there is another important meridian, which is the Greenwich antimeridian. It is located at 180° longitude and is considered the international day change line, that is, the point at which, in the time zone system, the day ends and a new one begins.
Modern applications of parallels and meridians
The geographic coordinate system based on parallels and meridians is used in many technologies and applications today:
- Global Positioning System (GPS). It is a system that uses a network of satellites so that GPS receivers calculate their exact position from latitude and longitude.
- Geographic information systems (GIS). They are software tools that allow the analysis and visualization of geographic data. They use geographic coordinates based on meridians and parallels to map and study phenomena such as population distribution, the expansion of cities or the use of land for agriculture.
- Digital maps and navigation applications Services like Google Maps and other navigation applications use geographic coordinates to locate and orient their users on maps.
document.addEventListener(“DOMContentLoaded”, (e) => {
var sliderContainer, slider;
sliderContainer = document.getElementById(‘block_ff6bf84969561ff1066b803f2d80a6c0’);
if (typeof initSlider !== ‘function’) {
console.log(‘Swiper haven\’t been loaded’);
sliderContainer.className += ‘ fw scroll-snap’;
return;
};
options = {
direction: ‘horizontal’,
speed: 1000,
slidesPerView: ‘auto’,
// slidesPerGroup: 1,
centerInsufficientSlides: true,
// centeredSlides:true,
spaceBetween: 15,
breakpoints: {
720: {
// centeredSlides: false,
// slidesPerGroup: 2,
spaceBetween: 25
},
},
pagination: {
el: ‘.swiper-pagination’,
type: ‘bullets’,
clickable: true
},
}
slider = initSlider(sliderContainer, options);
})
References
- National Geographic Institute. (sf). Parallels and meridians. Latitude and longitude. Didactic Atlas. https://educativo.ign.es/
- National Geographic Institute. (sf). Cartographic projections. Didactic Atlas. https://educativo.ign.es/
