In a Lambert projection, how are the lines that are equal distance apart described?

In a Lambert projection, the lines that are equal distance apart are referred to as standard parallels. This geometric property is characteristic of the Lambert conformal conic projection, which is particularly useful for mapping areas with greater east-west extent, such as the United States.

Standard parallels are specific latitudes where the projection maintains true scale. Between these parallels, distances are represented accurately, whereas scale distortion occurs outside this zone. This characteristic is vital for applications in navigation, aviation, and some forms of regional mapping, ensuring that measurements are reliable within the specified bounds.

The other terms listed—straight lines, central meridians, and meridians—do not specifically describe the lines that maintain equal distances in this context. While straight lines might refer to the paths of geodesic trajectories in other situations, they do not convey the concept of equal distance in the Lambert projection. Central meridians are the longitudinal lines that bisect the projection, and meridians are simply lines of longitude, neither of which designate the important feature of standard parallels. Thus, understanding standard parallels is crucial in interpreting Lambert projections accurately.