Why is the Mercator projection used on a map?
This projection is widely used for navigation charts, because any straight line on a Mercator projection map is a line of constant true bearing that enables a navigator to plot a straight-line course. It is less practical for world maps, however, because the scale is distorted; areas farther away from the Equator appear disproportionately large.
What is a transverse Mercator map?
Transverse Mercator. The Transverse Mercator map projection was invented by Johann Lambert and presented in 1772. Lambert rotated the Mercator cylindrical projection 90 degrees, making the tangent line a line of longitude instead of the equator. Only the central meridian and the equator of the projection are straight lines.
Why is linear scale constant on a Mercator projection?
Linear scale is constant on a Mercator projection in every direction, preserving the shapes and angles of small objects effectively. This fulfills the conditions of a conformal map projection. The side effect of this outcome creates the disadvantage of inflating the size of objects that are away from the equator.
When was the Mercator map invented?
Note: The methodology behind the map was probably in use before Gerardus Mercator's time, but it was so obscure that it is believed to have been independently reinvented by Mercator in 1569. Because the Mercator map projection is cylindrical, and a cylinder is open-ended, the projection in theory goes on forever.
Why is a straight line on a mercator projection map important?
This projection is widely used for navigation charts, because any straight line on a Mercator projection map is a line of constant true bearing that enables a navigator to plot a straight-line course. It is less practical for world maps, however, because the scale is distorted; areas farther away from the Equator appear disproportionately large.
What is a mercator projection?
The Mercator projection is a transformation of a cylindrical projection used for navigation. When the Portuguese, under the leadership of Prince Henry the Navigator, ventured farther south along the west coast of Africa, they encountered...
When was the Mercator projection invented?
Mercator projection, type of map projection introduced in 1569 by Gerardus Mercator. It is often described as a cylindrical projection, but it must be derived mathematically.
Is Greenland larger than South America?
On a Mercator projection, for example, the landmass of Greenland appears to be greater than that of the continent of South America; in actual area, Greenland is smaller than the Arabian Peninsula. The Mercator projection is a transformation of a cylindrical projection used for navigation.
Why does the Mercator map projection go on forever?
Because the Mercator map projection is cylindrical, and a cylinder is open-ended, the projection in theory goes on forever. This example has been "trimmed" before it reached 90 degrees north and south.
What is the effect of feature distortion on the Transverse Mercator map?
Feature distortion increases proportionally as the distance from the central meridian (the red vertical line) increases. For this reason, the Transverse Mercator map projection is applied to regions with a north-south orientation.
What is the name of the projection that represents the direction you need to sail to travel between the two points?
Knowing this, Gerardus Mercator invented a new projection based on the cylinder. Mercator invented his map projection primarily for navigation. If you draw a straight line between two points on a map created using the Mercator projection, that line represents the direction you need to sail to travel between the two points. This type of route is called a rhumb line or loxodrome. It is not the shortest route, but if you keep the direction of your ship constant with respect to north then you will stay on course and arrive at your destination.
What is the most famous map projection?
Without a doubt, the most famous map projection is the Mercator projection . In fact, the Mercator projection was the first projection regularly identified in atlases. It is a cylindrical map projection that is a product of its time.
What did Mercator do to make himself more acceptable to the gentry of the time?
On March 5, 1530, Mercator attempted to make himself more acceptable to the gentry of the time by adopting the Latin name for merchant as his surname and Latinizing his first name. He attended the University of Levine, in Flanders, where he originally studied philosophy and later astronomy and mathematics.
What was the second contribution of Mercator?
His second contribution was a map that still bears his name—the Mercator projection, published in 1569. Mercator called his map A New and Enlarged Description of the Earth with Corrections for Use in Navigation. No wonder future cartographers and laymen simply called it the Mercator projection.
When did Gerardus Mercator die?
Gerardus Mercator died on December 2, 1594, in Duisburg, in what is now Germany. (Snyder 1987, 1993, and Tooley 1987)
How to import lines into locator maps?
When creating a locator map, you might want to import some lines. To do so, you can go to geojson.io, draw a line and then copy the resulting JSON snippet to our GeoJSON import in locator maps.
Why do lines curve when they are close to the equator?
The further the lines are away from the equator, the more they will curve, because the more points on a map will be distorted when compared with a globe. Around the equator is almost no distortion, so the lines will appear straight like the red line here: 3.
Why are my maps not curved?
Lines on maps get curvy when they are long and go from the west to the east or the other way around. Here's are three reasons why your lines might be not curved: 1. Lines aren't shown as curves when they are short. As mentioned above, the distortion is only relevant when looking at small scale maps.
What projection do locators use?
Our locator maps use the Mercator projection. This works well for zoomed-in maps, but if you're showing entire continents the map will be distorted a lot. And because of this distortion, the straight line on a globe becomes an arc on a Mercator map.
What is a line in datawrapper?
A line is a connection between two coordinates. When you upload a line to Datawrapper, you're basically telling our tool: "Please find the shortest connection between these two coordinates." And that's what our locator map does.
What is map projection?
Wikipedia explains it well: "A map projection is a way to flatten a globe's surface into a plane in order to make a map. This requires a systematic transformation of the latitudes and longitudes of locations from the surface of the globe into locations on a plane. All projections of a sphere on a plane necessarily distort ...
Can you measure distance in Google Maps?
In case you want to play around with these curves (geographers call them great arcs or geodesics ), you can use the measure distance feature in Google Maps (make sure to switch to 2D view):
Why is it easier to plot courses on a mercator projection?
It is easier to plot courses on a Mercator projection.#N#The Mercator projection makes it easier to navigate over long distances on our planet because of two properties: straight rhumb lines and conformality. That means the courses and bearings that must be set are measured using protractors or wind roses, making it much easier to transfer directions from point-to-point on the map. All you need is a pair of navigational protractor triangles and a parallel ruler to determine where you need to be going.
How accurate is a mercator projection?
Although the scale approaches infinity when approaching the poles, the pros and cons of a Mercator projection show that it is one of the most accurate methods of staying true to navigational needs in the world today. That’s why this option will soon be celebrating its 500th anniversary of use.
Why is the Mercator projection useless?
Since you can navigate around the top of the arctic circle, the map becomes useless because you would need to go off the map to come back onto it. That makes its useless when you must navigate through those two regions of the planet.
What is the criticism of the Mercator projection?
There are some rightful criticisms of the Mercator projection in that it distorts some of the areas of the planet to make them seem more important than others to the casual observer. It is also the only map that provides an almost unerring certainty in navigational needs.
Which projection ensures that all lines on the map are straight and perpendicular to one another?
4. All cylindrical projections, meridians, and parallels are straight and perpendicular to one another. The Mercator projection ensures that all of the lines on the map are straight and perpendicular to one another, making it the only one where each primary direction remains true even though our planet isn’t flat.
Why is the climatological map method useful?
This method is useful for specific climatological maps and marine charts because it creates a display that offers features that are easier to read for the average person. This map option is named after the Flemish cartographer and geographer who invented it in 1569.
Can a mercator be used as a map?
If you have a Mercator projection to use as a map, then the information it provides you is not useful for the comparison of the area of the continents. This disadvantage can apply to the oceans as well since the waters near the poles encounter the same distortion that the landmasses experience.
Overview
Mathematics
Although the surface of Earth is best modelled by an oblate ellipsoid of revolution, for small scale maps the ellipsoid is approximated by a sphere of radius a, where a is approximately 6,371 km. This spherical approximation of Earth can be modelled by a smaller sphere of radius R, called the globe in this section. The globe determines the scale of the map. The various cylindrical projections specify …
History
There is some controversy over the origins of the Mercator. German polymath Erhard Etzlaub engraved miniature "compass maps" (about 10×8 cm) of Europe and parts of Africa that spanned latitudes 0°–67° to allow adjustment of his portable pocket-size sundials. The projection found on these maps, dating to 1511, was stated by Snyder in 1987 to be the same projection as Mercator's. However, given the geometry of a sundial, these maps may well have been based o…
Properties
As in all cylindrical projections, parallels and meridians on the Mercator are straight and perpendicular to each other. In accomplishing this, the unavoidable east–west stretching of the map, which increases as distance away from the equator increases, is accompanied in the Mercator projection by a corresponding north–south stretching, so that at every point location the east–west scale is th…
Distortion of sizes
As on all map projections, shapes or sizes are distortions of the true layout of the Earth's surface.
The Mercator projection exaggerates areas far from the equator.
• Antarctica appears to be extremely large. If the entire globe were mapped, Antarctica would inflate infinitely. In reality, it is the third smallest continent.
• Ellesmere Island on the north of Canada's Arctic archipelago looks about the same size as Australia, …
Uses
Practically every marine chart in print is based on the Mercator projection due to its uniquely favorable properties for navigation. It is also commonly used by street map services hosted on the Internet, due to its uniquely favorable properties for local-area maps computed on demand. Mercator projections were also important in the mathematical development of plate tectonics in the 1960s.
See also
• Cartography
• Central cylindrical projection – more distorted; sometimes erroneously described as the method of construction of the Mercator projection
• Conformal map projection
• Equirectangular projection – less distorted, but not equal-area
Bibliography
• Maling, Derek Hylton (1992), Coordinate Systems and Map Projections (second ed.), Pergamon Press, ISBN 0-08-037233-3.
• Monmonier, Mark (2004), Rhumb Lines and Map Wars: A Social History of the Mercator Projection (Hardcover ed.), Chicago: The University of Chicago Press, ISBN 0-226-53431-6