Aqua Survey provides board certified hydrographic / bathymetric surveying services worldwide. ASI owns and operates its equipment in estuaries, rivers, lakes, streams and ponds. Real-Time Kinematic Differential Global Positioning Systems (RTK-DGPS) can be used to provide centimeter-accurate vertical and horizontal control. Hypack Max™ is used for vessel control and tracking. Hydrographic sonar equipment emits sounds that travel to the bottom (depth of the water) and then bounce back to the sounder at the surface. The delay in the sound’s return to the surface is translated into water depth.Bathymetric (hydrographic) surveys provide clients with an accurate relief map of a pondbed, lakebed, riverbed or other area of interest.