In additon, very accurate measurements of the water properties are required throughout the survey so that compensations can be made for sound refraction, caused by density variations in the water. One great advantage of a hull-mounted array is that the survey can be run at relatively high speeds, making the surveys very cost effective. The USGS is using high-end graphic workstations with visualization software developed at the University of New Brunswick to analyze the multibeam datasets. An pixel on the image can be interrogated for latitude, longitude, depth, and slope and interactive profiles can be drawn across any area. Viewing data with these techniques provides an instant grasp of what the data actually depict.
Data processing is at the heart of any digital marine mapping operation.
Typically a team of USGS and OMG scientists processes the multibeam data while at sea. Final data editing, compilation, mosaicking, and plotting are completed within a day of the end of a cruise. The final maps of bathymetry and backscatter are readily transferred to a GIS for additional analyses and compilations.