Early hydrographic surveys consisted of depths calculated by sounding pole and hand lead line, with positions based on a few-position sextant fixes to mapped reference factors. Guide lines were being ropes, or traces, with depth markings and guide weights hooked up. Hydrographic surveying requires measuring all components beneath the h2o’s https://griffinebptx.thelateblog.com/32735269/5-essential-elements-for-hydrographic-survey-in-bangladesh