This distortion stretches landmasses like Greenland and Europe and they appear much bigger than places that are close to the equator such as South America and Africa. Despite these errors the popularity of the projection as a navigation aid and its easily readable rectangular grid meant that it was easy to reproduce in printed materials like atlases and wall maps. As a result, it became a standard map for classrooms. Throughout the s geographers and scholars have claimed that the Mercator projection is incorrect and that it should only be used for navigation.
It was not until the s though that the projection began to receive wide criticism. In for instance, seven professional geographic organizations in North America adopted a ban on this and other rectangular coordinate maps Rosenberg.
Greenland, for instance is not bigger than South America, but it appears to be on Mercator maps. Other critics say that this projection and the large size of continents like Europe gave an advantage to the colonial powers because it made them appear larger than they really are.
This advantage eventually led to the lack of development in many equatorial regions that appear smaller on the Mercator maps. Despite these criticisms, there is use for the Mercator projection in sailing and world exploration because it does allow for easier navigation.
In addition, it is an interesting example of how a map projections can make areas of the world appear in certain ways. Chang, Kang-tsung.
You cannot download interactives. Whether your map is paper or digital, mastering the basics of reading it are vital to finding your way around and understanding how the world works. Maps are fantastic visual tools that can help us communicate spatial concepts and patterns, tell stories, and analyze data. However, there are some challenges to translating Earth onto a flat surface without adding bias or inaccuracies. Fortunately, cartographers have the training to minimize these issues.
Maps have been a part of the National Geographic Society since the beginning. Gilbert H. It's lines and colors show the realization of great dreams. A map is a symbolic representation of selected characteristics of a place, usually drawn on a flat surface.
Students look at lines of latitude and longitude on United States and world maps, discuss why these lines are helpful, and identify landmarks with similar latitude and longitude.
Cartographers at National Geographic discuss how they select an appropriate map projection for the September issue. Join our community of educators and receive the latest information on National Geographic's resources for you and your students. Skip to content. Image Mercator World Map Geradus Mercator's world maps flattened the spherical planet to make it easier to display. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Mercator variant A differs from variant B only in projection parameters.
They share the same algorithm. Mercator variant C differs from variant B only in projection parameters. The poles cannot be represented on the Mercator projection. Large area distortion makes the Mercator projection unsuitable for general geographic world maps and thematic mapping. It is the de facto standard for web maps and online services.
With this coordinate system, the geodetic coordinates defined on the WGS 84 datum are projected as if they were defined on a sphere, using a sphere-based version of the Mercator projection. The sphere's radius is equal to the WGS semimajor axis, Combining geodetic coordinates on the ellipsoid with spherical equations consequently leads to a coordinate system that does not preserve the scale factor in all directions.
Therefore, the Web Mercator coordinate system is not conformal, and besides enormous area and distance distortions away from the equator, it also does not project rhumb lines as straight lines. Two methods exist for emulating the Mercator projection used by the web services.
If the Mercator implementation supports spheroids ellipsoids , the projected coordinate system must be based on a sphere-based geographic coordinate system. This will force the use of sphere equations. The implementation of Mercator auxiliary sphere has sphere equations only.
The projection seats a series of cones over a globe with the axis of each cone lapping over the axis of a globe, creating parallels in equal number to that of the tangent cones.
The parallels are arcs of circles that are not concentric, but are equally spaced along the central meridian. The parallels and meridians are curves, except the equator which is a straight line. As both parallels and meridians are more curved at the periphery, there is possibility that the scale distortion grows. This type of map projection is commonly used for map-making in an area that extends in north-south direction.
Cylindrical equal area projection. The projection places a cylinder to touch a globe at normal positions. All the parallels and meridians are straight lines crossing each other at the right angles.
Every parallel is in the same length as the equator on the globe. Gall invented this type of map projection by using a cylinder to intersect the globe at the 45th parallel north and south, resulting in less distortion around both poles. Parallels and meridians are all straight lines intersecting each other at right angles. The parallel spacing increases in the areas closer to the poles. Mercator invented this type of projection in the 16th Century and it has been commonly used ever since. This projection uses a cylinder to touch a globe at the equator plane and cast the light for meridians and parallels to appear on cylindrical surface.
Meridians are straight lines and equally spaced, while parallels are also straight lines but their spacing increases as they get closer to the poles. Shapes are represented more accurately in tangent point areas. However, the closer to the poles, the more distortion occurs.
Therefore, it is not typically used to make a map in areas above 80 degrees north latitude and below 80 degrees south latitude. The Mercator projection is being applied in varying patterns, such as by taking a cylinder to touch a globe with the axis of cylinder intersecting that of the globe at the right angle, leaving the cylinder to touch any single meridian.
By that way, a central Meridian is created. When the cylinder is unrolled, the area adjacent to the central meridian will have constant scales.
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