Hey geography fans and aspiring cartographers: Ready to put the gall-peters map projection to the test? Our free Gall-Peters map projection quiz challenges you to identify what type of distortion does the gall peters projection preserve - while contrasting it with the Mercator map projection and even mentioning the boggs eumorphic projection. Whether you're a seasoned cartographer or just love maps, you'll uncover surprising insights about area, shape, and more. Take our globe quiz to compare styles, then sharpen your map skills and prove your prowess. Jump in now and start exploring!
What type of map projection is the Gall-Peters projection?
Conformal cylindrical
Azimuthal equidistant
Cylindrical equal-area
Pseudocylindrical equal-area
The Gall-Peters projection is a specific case of the cylindrical equal-area family of map projections, meaning it preserves area across the map. It was developed to address the size distortions found in conformal projections like Mercator. Because its vertical and horizontal scales vary with latitude, it retains accurate proportional areas for each region. For more details, see Wikipedia.
Which property does the Gall-Peters projection preserve?
Area
Distance
Direction
Shape
The Gall-Peters projection is designed as an equal-area projection, ensuring that regions on the map have areas proportional to their areas on the globe. This comes at the cost of distorting shapes, especially near the poles and equator. It does not preserve distance or true direction across the entire map. Learn more at National Geographic.
Who popularized the Gall-Peters projection in the 1970s?
Johann Lambert
Gerardus Mercator
Arno Peters
James Gall
Although the projection's formulas date back to James Gall in the mid-19th century, it was German historian Arno Peters who championed it during the 1970s. Peters argued that equal-area projections offer a fairer view of world geography compared to Mercator. His advocacy led to its modern name, the Gall-Peters projection. More history is available at National Atlas.
Compared to the Mercator projection, how does the Gall-Peters projection depict regions near the equator?
They appear upside down
They appear much smaller
They appear more proportionally accurate
They appear elongated horizontally
The Mercator projection inflates the size of regions far from the equator and compresses equatorial regions, making the latter appear smaller than they are. The Gall-Peters projection corrects this by preserving area, so equatorial regions appear in correct proportion to higher latitudes. This equal-area property ensures a fairer size comparison. See ScienceDirect for more.
In the Gall-Peters projection, continents near the poles appear:
Rendered at true shape
Compressed horizontally
Elongated vertically
Mirrored upside down
Because the projection maintains equal area by stretching vertical distances away from the equator, regions near the poles are elongated in the vertical direction. This shape distortion is the trade-off for preserving area. The further from the standard parallels (±45°), the greater the vertical stretching. More on this effect at Red Blob Games.
What is a common criticism of the Gall-Peters projection?
It makes all distances equal
It does not preserve area
It can't be drawn on a cylinder
It distorts the shape of landmasses significantly
While Gall-Peters maintains accurate area relationships, it drastically distorts the shapes of continents and countries, especially near the poles and equator. Critics argue that this distortion can mislead viewers about the true shape of landmasses. The projection's vertical stretching is the root cause of these shape changes. For more critique, see Cartographic Perspectives.
The Gall-Peters projection is mathematically equivalent to which earlier projection?
Behrmann cylindrical projection
Lambert cylindrical equal-area projection
Mercator cylindrical projection
Mollweide projection
The Gall-Peters projection is a specific case of the Lambert cylindrical equal-area projection with standard parallels at the equator. This makes it mathematically identical in how it scales the globe's latitudes and longitudes. The only difference is the naming and popular advocacy by Peters. Further information is available at USGS Professional Paper.
At what latitudes are the standard parallels in the Gall-Peters projection?
0° only
±60°
±23.5°
±45°
The Gall-Peters projection uses ±45° as its standard parallels, meaning at those latitudes true scale is maintained. Parallel spacing between those lines is equal, and distortions increase beyond them. This choice of standard parallels helps balance the vertical stretch and horizontal compression. Read more at Oregon State University.
Which international organization recommended the Gall-Peters projection in 1989 for educational maps?
World Bank
Greenpeace
UNESCO
United Nations
In 1989, UNESCO endorsed the use of equal-area projections such as Gall-Peters for educational purposes, promoting a fair representation of countries' sizes. The goal was to avoid Eurocentric biases common in Mercator maps. UNESCO's recommendation sought to improve geographic literacy in schools worldwide. Details can be found at UNESCO Document.
While preserving area, the Gall-Peters projection introduces significant distortion in:
Latitude coordinates
Shape and angles
Direction only
None of the above
Area preservation in Gall-Peters requires sacrificing conformality, so shapes and angles are highly distorted. This distortion grows near the poles and equator because meridians and parallels are not orthogonal at proper scales. Directions across the map are not uniform. For a deeper dive, see Springer Reference.
Which class of projections does Gall-Peters belong to?
Azimuthal
Equal-area
Equidistant
Conformal
Gall-Peters is categorized as an equal-area projection because it maintains surface area proportions for all regions. It is not conformal (shape-preserving) or equidistant (distance-preserving). The equal-area class includes other projections like Mollweide and Albers conic equal-area. More info at Penn State GEOG.
Who first described the equal-area projection now known as Gall-Peters in 1855?
James Gall
Johann Lambert
Arno Peters
John Snyder
James Gall, a Scottish clergyman and mapmaker, first presented the cylindrical equal-area projection in 1855. His work went largely unnoticed until Arno Peters reintroduced it over a century later. Gall's formulation forms the mathematical basis for today's Gall-Peters projection. See the original paper at Internet Archive.
How does the spacing of parallels in Gall-Peters compare to those in Mercator?
Parallels are equally spaced
Parallels are closer near the poles
Parallels follow a sinusoidal pattern
Parallels converge at the equator
In the Gall-Peters projection, parallels of latitude are drawn at equal vertical intervals, reflecting the projection's equal-area nature. By contrast, Mercator's parallels spread apart exponentially toward the poles. Equal spacing ensures area preservation but distorts shapes away from the standard parallels. More details are on Map-Projections.net.
Which organization's national curriculum controversially adopted the Gall-Peters projection in the 2000s?
UK government
United States Department of Education
Canadian Ministry of Education
Australian Curriculum Council
The UK government adopted the Gall-Peters projection for school geography curricula in the early 2000s, sparking debate among educators and cartographers. Proponents praised its equal-area representation; critics pointed to shape distortion. This choice highlighted political dimensions of map design. More context at The Guardian.
What is the scale factor along the standard parallels in the Gall-Peters projection?
2
1
0.5
It varies with longitude
The standard parallels of the Gall-Peters projection at ±45° have a scale factor of 1, meaning true distances are represented along those lines. At other latitudes, the projection stretches or compresses distances to maintain equal area. This characteristic is fundamental to equal-area cylindrical projections. For mathematical details, see EPSG.io.
Which projection is also a cylindrical equal-area but uses standard parallels at ±30°?
Miller cylindrical projection
Robinson projection
Behrmann projection
Eckert IV projection
The Behrmann projection is a variant of the cylindrical equal-area family with standard parallels at ±30°. Like Gall-Peters, it preserves area but distorts shape differently due to its choice of standard parallels. This shifts the zone of minimal distortion closer to the tropical regions. More at Wikipedia.
In the Gall-Peters projection, what is the formula for the vertical (y) coordinate on a sphere of radius R?
y = R ln(tan(?/4 + ?/2))
y = R sin(?)
y = R tan(?)
y = R ?
For a cylindrical equal-area projection like Gall-Peters, the vertical coordinate is given by y = R·sin(?), where ? is latitude. The horizontal coordinate is x = R·(? - ??). This formulation ensures that the area element is constant across the map. For derivation, see Penn State GEOG.
Which property does the Gall-Peters projection explicitly sacrifice in order to preserve area?
Scale along the equator
Meridian convergence at poles
Conformality (shape preservation)
Equal spacing of meridians
Equal-area projections like Gall-Peters must sacrifice conformality, meaning angles and local shapes are not preserved. The trade-off ensures each region's area remains true to its real-world size but distorts local geometry. In contrast, conformal projections like Mercator preserve shape at the expense of area. More on this trade-off at EPSG.
Which distortion is minimal at the standard parallels of the Gall-Peters projection?
Shape distortion
Direction distortion
Scale distortion
Area distortion
At the standard parallels (±45°), scale distortion is minimized, meaning distances along those lines are true to scale. However, shape distortion still exists to maintain equal-area properties. Directions and angles remain distorted except at isolated points. For an in-depth analysis, see Springer.
The Gall-Peters projection influenced which modern GIS EPSG code for cylindrical equal-area?
EPSG:3857
EPSG:3395
EPSG:4326
EPSG:54002
EPSG:54002 is the code for the World Cylindrical Equal Area projection, which corresponds to the Gall-Peters projection parameters. It is commonly used in GIS systems to implement area-preserving cylindrical maps. Other EPSG codes refer to different projections like Web Mercator or WGS84. See EPSG.io for details.
Why was the Gall-Peters projection promoted as a political statement?
To replace polar azimuthal maps
To highlight economic power
To counter Eurocentric size distortions
To emphasize navigation accuracy
Proponents of the Gall-Peters projection argued that Mercator maps exaggerated the size of Europe and North America, reinforcing colonial mindsets. By preserving area, Gall-Peters levels the visual playing field, offering a more equitable depiction of developing nations. Its adoption became a symbol of decolonizing cartography. See The Guardian.
How does angular distortion in the Gall-Peters projection vary with latitude?
It peaks at the equator and poles equally
It is zero only at the poles
It increases smoothly from the standard parallels toward poles and equator
It is uniform across all latitudes
Angular distortion in the Gall-Peters projection is minimal at the standard parallels (±45°) and increases as one moves toward the poles or equator. This is because the projection stretches or compresses distances differently in meridional and parallel directions. Equal-area requirements force these angular distortions. For mathematical proof, see Springer.
What is the ratio of meridional scale to parallel scale at latitude ? in the Gall-Peters projection?
tan ? : cot ?
1/cos ? : cos ?
cos ? : 1/cos ?
1/cos² ? : 1
In an equal-area cylindrical projection, meridional scale k? = 1/cos ? and parallel scale k? = cos ?, ensuring k?·k? = 1. Thus the ratio k?:k? = (1/cos ?) : (cos ?). This ratio quantifies the directional distortion away from standard parallels. Detailed derivation is at Penn State GEOG.
Which ESRI projection code corresponds directly to the Gall-Peters projection?
900913
54002
4326
54003
In ESRI's format, the code 54002 identifies the World Cylindrical Equal Area projection configured with Gall-Peters parameters. This code directs GIS software to use the exact projection rules Peters promoted. Other common codes like 4326 refer to geographic coordinate systems rather than equal-area projections. Verify at ESRI Support.
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AI Study Notes
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Study Outcomes
Understand Gall-Peters Map Projection -
Learn the equal-area foundation of the gall-peters map projection and its role in representing landmass proportions accurately.
Identify Preserved Distortion -
Recognize what type of distortion the gall-peters map projection preserves and why area accuracy is prioritized over shape.
Compare to Mercator Map Projection -
Contrast the gall-peters map projection's area fidelity with the Mercator map projection's shape-preserving approach.
Contrast with Boggs Eumorphic Projection -
Examine how the boggs eumorphic projection differs from the gall-peters map projection in balancing area and angular distortions.
Analyze Projection Impact -
Assess how choosing different projections shapes our perception of global geography and influences data interpretation.
Apply Cartographic Concepts -
Use your understanding of these projections to make informed decisions in map-based quizzes and real-world mapping applications.
Cheat Sheet
Equal-Area Distortion Preservation -
The Gall-Peters map projection is an equal-area projection that preserves the true proportional size of countries, answering "what type of distortion does the Gall Peters projection preserve." A simple mnemonic - "Every Country's Shape Adjusts, Area Intact" - helps you recall that area is sacrosanct. According to the United Nations Cartographic Section, this approach combats the size exaggeration seen in other projections.
Shape Distortion Trade-Offs -
While area remains accurate, shape distortion increases toward the poles and equator, stretching landmasses vertically or horizontally. Remember "Tall near Equator, Wide by the Poles" to visualize how Africa and South America look elongated. The University of Texas Map Library notes these shape shifts as the cost of true-area mapping.
Core Projection Formula -
Mathematically, the Gall-Peters projection uses x = R·λ·cos 45° and y = R·φ / cos 45°, where R is Earth's radius, λ longitude, and φ latitude. This yields x = 0.7071R·λ and y = 1.4142R·φ, balancing horizontal and vertical scales at the 45° standard parallels. ESRI documentation highlights this concise formula as key to reproducing equal-area results in GIS software.
Contrast with Mercator Map Projection -
The Mercator map projection preserves angles and shapes locally (conformal) but grossly inflates high-latitude regions like Greenland. By comparison, the Gall-Peters projection sacrifices shape fidelity for accurate area, offering a more politically equitable view of nation sizes. NOAA emphasizes this trade-off when teaching the differences between conformal and equal-area methods.
Comparison to Boggs Eumorphic Projection -
Like Gall-Peters, the boggs eumorphic projection is equal-area but blends characteristics of cylindrical and pseudocylindrical formats, reducing distortion in mid-latitudes. A handy tip: think "Boggs Brings Balanced Bends" to recall its smoother transitions compared to the more angular Gall-Peters. The International Cartographic Association highlights that Boggs offers a middle ground for those needing both area and moderate shape preservation.
