SonarTRX lets you import, view and create Google Earth images from your sonar recordings on your PC. (Supports Humminbird side-imaging units and Lowrence StructureScan xtf files)
You can then keep track of your most interesting fishing/diving/survey-areas using kml files and ground-overlay images (w/Google Earth)
Waypoints and annotations from your sonar recordings can also be managed with Google Earth as kml placemarks and converted back to gpx with SonarTRX (for transfer & display on the sonar/nav.system.)
For more information, please visit:
www.sonartrx.com
Tore