Patent ID: 9329267
Filing Date: 2016-05-03
CPC Classification: G01C,G01S

Claim Text:
1. A method for displaying, on a display device carried on a surface water craft traversing a body of water, a depth chart for the body of water, the chart being established on the basis of a standard water level for the body of water, the method comprising the steps of: providing a digitized nautical chart for a geographic area that includes the body of water and adjacent shoreline, the chart being stored in a non-transitory computer-readable storage medium, the chart defining a plurality of different depth ranges, the chart including information specifying the regions of the geographic area occupied by each of the depth ranges, the chart further including a unique depth range indicator for each depth range, the depth range indicator generally indicating a depth value of the depth range; obtaining, using at least one sonar transducer, sonar data at each of a plurality of locations along a depth ring of the chart, wherein the sonar transducer produces and receives electronics signals indicative of depth; calculating, using a sonar signal processor and based on the sonar data, a sonar-indicated depth corresponding to each of the plurality of locations along the depth ring; determining an average sonar indicated depth for the depth ring based on each sonar indicated depth for the plurality of locations along the depth ring; determining a chart-indicated depth corresponding to said depth ring; calculating a water-level offset for the depth ring based on a comparison between the average sonar-indicated depth for the depth ring and the corresponding chart-indicated depth for the depth ring; adjusting each of the depth range indicators for the depth ring based on the water-level offset; and displaying on the display device the chart with the adjusted depth range indicators.