| Value |
| Land |
| Singlebeam |
| Multibeam |
| Seismic |
| Isolated sounding |
| ENC Sounding |
| Lidar |
| Depth measured by optical light sensor |
| Combination of direct measurement methods |
| Predicted based on satellite-derived gravity data |
| Interpolated based on a computer algorithm |
| Digital bathymetric contours from charts |
| Digital bathymetric contours from ENCs |
| Depth from multiple sources including measured, derived, and interpolation |
| Predicted based on helicopter/flight-derived gravity data |
| Depth estimated by calculating the draft of a grounded iceberg |
| Depth derived from grounded Argo float data |
| Depth measured by animal-borne data loggers |
| Pre-generated grid |
| Unknown source |
| Steering points |