# Do you mean the Earth's grid?

The Earth's Grid System On geographic maps and globes, the meridians and parallels help to delineate the geographic coordinates of places on the earth's surface—the latitudes and longitudes. Every location on a particular meridian has the same longitude, and every point on a parallel has the same latitude. The lines connecting these two points make up the borders of the different regions on the globe.

Geographers use the word "grid" to describe the pattern formed by sets of parallel and perpendicular lines marking out blocks of land or sea. This pattern is found everywhere that land exists, from the largest scales down to the level of individual plots of land. At the global scale, the main features of the grid system are the circles of constant longitude called "walls" and the circles of constant latitude called "islands."

At the continental scale, the main features are the parallels of latitude forming the boundaries between countries or other political entities, such as the United States and Canada. These borders are also marked by large bodies of water within each country/state; however, they do not constitute separate islands because there are no perpendicular distances between them.

At the regional scale, the main features are the patterns of land and water that define the locations of major cities. Here, the parallels of latitude serve as the boundaries between states or provinces, while the oceans represent the only real obstacles between places far apart on the map.

## Do latitude and longitude have a grid?

Grids for latitude, longitude, and the Spherical Coordinate System When two coordinates (X and Y) are combined, they may be used to find anything on Earth. Our coordinate system's grid is made up of latitude and longitude. These are two-dimensional divisions that divide the surface of Earth into boxes called cells. The further away from the equator you go, the more cells there are in a single degree of latitude or longitude. Every six degrees of latitude or longitude is called a degree line.

The cell size gets smaller as we move away from the equator or closer to the center of Earth. At the poles, there are no degrees of longitude or latitude; instead, there are 90 degrees of longitude or latitude. The word "pole" comes from polus, the Greek word for whole. There are also two special points on the coordinate system grid: the North Pole and the South Pole. They are represented by zero degrees of longitude or latitude.

At the North Pole, all the cells in one degree of latitude are empty, because there are no places where it would be possible to find something within that degree of latitude. At the South Pole, all the cells in one degree of longitude are empty, because there are no parts of Antarctica that are accessible to human beings.

## Is the equator in the grid system?

Much of the Earth's grid system is built on the North Pole, South Pole, and Equator. The poles are located at the endpoints of an imaginary line drawn from the Earth's rotating axis. The equator's plane is a fictitious horizontal plane that divides the globe into two equal half. The equator itself is the name given to the circle that forms when any point on the surface of the Earth is connected to the center of the planet by a straight line.

The prime meridian is the great circle passing through both poles from pole to pole. It serves as a reference for measuring time across the world. The International Atomic Time (TAI) keeps correct time at both poles and on the prime meridian.

Time zones were invented by American inventor and engineer George Washington Bailey. The idea came after the American Civil War when there was no agreement on which part of the country should be considered "east" or "west". In 1872, President Ulysses S. Grant appointed a committee that recommended that the country adopt standard time hours for commercial shipping. These recommendations formed the basis for today's time zones.

Each zone is assigned a single hour when standard time starts and ends. The interval between these hours is GMT+01:00 and GMT+03:00. The central time zone covers most of North America and parts of Europe and Asia. The eastern time zone covers most of Canada and all of the United States except for Alaska.

## How do you read a global grid?

The worldwide grid system employs both latitude parallels and longitude meridian. When describing a place in terms of latitude and longitude, the latitude is always given first. New Orleans, for example, is located at 30 N and 90 W. This is written as 30° north latitude and 90° west longitude. The map coordinates are used when referring to a specific location on the map.

In addition to these two parallel lines that divide the world into six equal parts, the worldwide grid uses three more meridians at 60° intervals: the Greenwich Meridian, which passes through Greenwich, England; the Central Meridian, which runs through Washington, D.C.; and the North American Meridian, which crosses the border between Canada and the United States. These meridians are marked with red lines on most modern maps.

The Greenwich Meridian is the basis for all measurements of time across the world. It is also known as 0° longitude. All hours, minutes, and seconds are measured from this point along the equator. GMT is the name given to the number of hours past midnight at the Greenwich Observatory, which is equivalent to the hour angle above the ground at either side of the globe. For example, London time is one hour ahead of GMT, so it is 15 hours after midnight at the Greenwich Observatory. California time is five hours behind GMT, so it is 2 am at the Greenwich Observatory.

##### Louise Tisby

Louise Tisby is an expert on gemology and mineralogy. She has been studying these subjects for over 15 years, and she is passionate about her work. Louise loves to share what she knows about these subjects, because she believes that knowledge is power!