THE 5-SECOND TRICK FOR HYDROGRAPHIC SURVEY IN DHAKA

Early hydrographic surveys consisted of depths calculated by sounding pole and hand guide line, with positions determined by a few-place sextant fixes to mapped reference points. Guide lines had been ropes, or strains, with depth markings and guide weights hooked up.Many of the prior information during the job area spans through the 1880s to 1970s.