Some map keys show land elevation using two measurements. What are these two measurements?

Answer 1

Feet and meters I believe, unless I'm misinterpreting the question.

Answer 2

Your question is confusing because I've never seen a key which references height. Even topographical maps only show elevations by color. Height, if it were to be measured would likely be by foot and by meter. This, in turn could be measured either in pure height or distance above sea level. For example, Mt Everest is the highest mountain - above sea level. However, Mt McKinley/Denali is actually a taller mountain. Its base simply lies at a lower sea level. The primay key on a map is that depicting distance and is shown in both meters and miles.