On which type of map would Nigeria be bigger than Australia?

A cartogram of population is designed to visually represent the size of geographic areas according to a specific variable, in this case, population. In such maps, countries are resized based on the number of people living in them rather than their actual land area.

Nigeria, with a population exceeding 200 million, would occupy a larger area on a cartogram compared to Australia, which has a much smaller population of about 25 million. This dramatic resizing allows viewers to see the relationship between population size and geographic area visually, often resulting in countries with large populations appearing much larger than they are geographically.

Other types of maps mentioned do not serve this purpose. For example, a contour map of elevation focuses on landform height, a flow-line map of spice trade illustrates trade routes, and the Mercator projection distorts land sizes based on latitude, generally making regions near the poles appear larger than they are relative to those near the equator. Hence, Nigeria's portrayal as larger than Australia only occurs on the population-based cartogram.