In a Lambert projection, with what does the scale factor vary?

In a Lambert projection, the scale factor varies primarily with latitude. This specific type of projection is designed to accurately represent areas in mid-latitude regions. The scale factor changes as you move away from the standard parallels, which are the latitudes where the projection maintains true scale.

In the context of mapping, the scale factor is a measure of how much the map distorts distance compared to the real world. Near the standard parallels, the map has minimal distortion, but as one moves further north or south from these parallels, distortion increases due to the curvature of the Earth being represented on a flat surface.

Longitude does not affect the scale factor in a Lambert projection because the projection is designed to manage distortion more effectively in the latitude dimension while often using the same scale in the longitudinal sense, especially along the standard parallels. Thus, the correct response highlights the significance of latitude in determining the variations in scale within a Lambert projection framework.