projection

Matt Parker of Stand-up Maths asks whether a country's reported land area accounts for hills and mountains, working through how surface area depends on the resolution of elevation data. It follows up on a question from a viewer and work by researchers who measured it.

Wendover Productions explains how the US military moves people and materiel worldwide, including prepositioned equipment, sealift and airlift. It shows the scale of the logistics system behind US force projection.