What key characteristic defines a Transverse Mercator projection?

A Transverse Mercator projection is primarily defined by its orientation and distortion characteristics, making it particularly well-suited for mapping areas that have a north-south layout. This projection works by projecting the geographic coordinates of the Earth onto a cylinder that is aligned along a meridian, or line of longitude. Because the projection is tangent to the central meridian, it minimizes distortion along this line and thus provides accurate representations of distances, angles, and shapes for regions extending north and south from this meridian.

The focus on north-south orientations makes this projection advantageous for applications such as topographic mapping, cadaster, and other local mapping endeavours in areas that fit this description. The other characteristics mentioned, such as wrapping the globe around a cylinder, while relevant, do not encapsulate the main utility of the projection in terms of geographic areas it best serves.