Hydrographic Surveying 400 x 321 - 54k - gif surveying.wb.psu.edu | sonar diagram 318 x 273 - 118k - gif marine.usgs.gov | WHSC Sidescan Sonar systems 460 x 283 - 30k - jpg woodshole.er.usgs.gov | sonar. ... 608 x 507 - 28k - png www.wh-hms.uni-ulm.de | ... sonar arrays and magnetometers. 370 x 312 - 15k - jpg www.fas.org | Sonar Timeline 1916: Approx. 830 x 624 - 60k - jpg www.de220.com |