Surveyors have to be careful to know your situation also to calibrate the echo sounder. Often, it can be hard to determine the actual base due to existence of a column of soppy mud close to the sea mattress. A dual frequency echo sounder assists in this example to determine https://hydrographic-survey-in-dh96295.anchor-blog.com/12736809/hydrographic-survey-in-dhaka-no-further-a-mystery