Final answer:
The primary weakness of an equal area projection is that it alters or distorts the shape of landmasses, although it maintains the correct area size. The Mercator projection, in contrast, distorts the size, especially at higher latitudes, making regions like the US appear similar in size to Africa, when in fact Africa is much larger.
Step-by-step explanation:
The question asks about the weakness of an equal area projection map. An equal area projection is a map that maintains the true size of landmasses across the map, meaning the areas depicted are proportional to the same areas on the Earth. The primary weakness or disadvantage of the equal area projection is that it alters or distorts the shape of land masses to achieve this proportionality. Especially near the poles, the projection stretches the landmasses to maintain equal areas, resulting in distorted shapes that do not represent the true appearance of these regions.
While the equal area projection addresses the issue of distortion of size seen in projections like the Mercator, it introduces a trade-off by distorting shapes. Unlike the Mercator projection, which makes high-latitude regions look larger than they actually are, the equal area projection avoids this problem but does so at the expense of shape accuracy.
Using tools like The True Size allows for an interactive comparison of true landmass sizes, helping to visualize how different projections represent the same areas differently. It's important to understand the strengths and weaknesses of each map projection to avoid misinterpretations, such as underestimating the size of a region or incorrectly assessing the distance between two points due to the type of map used.