hydrographer
a. நிலவுலக நீர்நிலைப் பரப்பாராய்ச்சித்துறை வ்ல்லுநர்.
Hy*drog"ra*pher, n. Defn: One skilled in the hydrography; one who surveys, or draws maps or charts of, the sea, lakes, or other waters, with the adjacent shores; one who describes the sea or other waters. Boyle.