Urban Dortet de Tessan (August 25, 1804 – September 30, 1879) was a French physicist and Hydrographer Engineer active in Paris during the early to middle part of the 19th century. Tessan was considered among the most scientific of cartographers active at the time and his work is notable for its meticulousness and precision. Tessan was born I Vigan, the scion of an old Languedoc family. He graduated from the École Polytechnique in 1825. Afterwards he completed detailed surveys of the coast of France. From 1836 to 1839 he traveled around the world making scientific observations on the frigate Venus under the command of Abel Aubert Dupetit-Thouars. Tessan published several important works on physics, hydrography, astronomy, and more. Some of his more significant research presaged the invention of sonar over one hundred years later.