In an equal-area map projection, which feature is proportional to the corresponding area on Earth?

In an equal-area map projection, which feature is proportional to the corresponding area on Earth?

• A. Areas on the map are proportional to corresponding areas on Earth
• B. Distances on the map are preserved from the center
• C. Angles are preserved at every point
• D. Directions are preserved along features

Answer: (A)

Equal-area projections focus on keeping size relationships intact. The map is shaped so that the area of any region on the map is directly proportional to its true area on Earth, meaning a land area that’s twice as large on Earth appears twice as large on the map. This constant area scale is what preserves proportionality of areas, even though the shapes may be stretched or squashed. Because the trade-off is in shape and angle accuracy, angles aren’t preserved at every point and distances or directions aren’t generally true across the map. An example is the Mollweide projection, which keeps area proportional but distorts coastline shapes. So the feature that remains proportional is the area: areas on the map reflect corresponding areas on Earth.

Equal-area projections focus on keeping size relationships intact. The map is shaped so that the area of any region on the map is directly proportional to its true area on Earth, meaning a land area that’s twice as large on Earth appears twice as large on the map. This constant area scale is what preserves proportionality of areas, even though the shapes may be stretched or squashed. Because the trade-off is in shape and angle accuracy, angles aren’t preserved at every point and distances or directions aren’t generally true across the map. An example is the Mollweide projection, which keeps area proportional but distorts coastline shapes. So the feature that remains proportional is the area: areas on the map reflect corresponding areas on Earth.