Bathymetric Mapping

How can ocean floor features be measured and mapped using current acoustical technology? How can ocean floor maps be used in the commercial, military, and/or private sector? 

Ocean floor features are mapped using sonar. Sound is bounced off the ocean floor, the rate at which it comes back shows what the floors look like. Ocean floor maps are used to navigate the ocean so no one hits a ridge or goes over a section where magma might be flowing out.

A map of the ocean floor

Our seafloor was mostly flat but had a ridge on one side. Using remote sensing technology is better than direct observation because it allows you to know the actual size of the features and their depths. Vertical exaggeration is helpful because it allows the features to be exaggerated so it is easier to see them. This activity was valuable to my science knowledge because It helped me to see the advantage of using sonar to map the ocean seafloor. Are there any problems with using sonar to map the ocean floor features? If we have this technology, why haven't we been able to map the whole ocean floor?