Early hydrographic surveys consisted of depths measured by sounding pole and hand guide line, with positions determined by 3-place sextant fixes to mapped reference details. Direct traces were being ropes, or strains, with depth markings and lead weights attached. The coastal space of Bangladesh is rather shallow and indented in https://edgarrnvuw.p2blogs.com/31531843/not-known-details-about-hydrographic-survey-in-bangladesh