Question

does mean sea level have contour value zero?​

Answer 1

Explanation:

The contours on a topographic map tell us the elevation of points directly under those lines. You can think of the contour lines like water levels rising up on an island. Sea level, 0', the coast line, is a the first contour line.

Answer 2

Answer:

The water surface marks an elevation we call sea level, or zero. As you walk along the shore your elevation will remain the same; you will be following a contour line. If you stray from the shoreline and start walking into the ocean, the elevation of the ground (in this case the seafloor) is below sea level.