a marine map utilized to identify depth variances in bodies of water. Nautical charts can be found for both fresh and saltwater fishing. The meat of the map is the "soundings" that are reflected in numbers that represent fathoms. Each fathom is a measurement of six feet.
A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land, natural features of the seabed, details of the coastline, navigational hazards, locations of natural and man-made aids to navigation, information on tides and currents, local details of the Earth's magnetic field, and man-made structures such as harbours, buildings and bridges. Nautical charts are essential tools for marine navigation; many countries require vessels, especially commercial ships, to carry them.