A nautical chart (map) shows the shore and land-marks, sea bed conditions, navigation hazards, buoyed channels, and so on, relating to the safe navigation of vessels and inshore boats.
it's called a chart. Nautical maps are referred to as "Charts".
nautical
Different kinds of maps are created for different purposes. To navigate from one place to another, one would prefer a physical (geographic) map, but to locate a country, one would need a political map and a world map is for the world. Further refinements include road maps, topographic maps, nautical and aeronautical charts, each of which represent more physical details. Thematic maps can be used to display distribution of various measurements, such as people, oil, cellphone coverage, etc.
The Mercator map was created in 1569 by Gerardus Mercator. The projection's creator wanted to create a map that would be helpful in navigating the world's seas. The map is set up on a useful grid. However, the map is clearly distorted! At the north and south ends of the map, Antarctica and Greenland are just two examples of landforms that appear far bigger than they should. Areas and distances are not portrayed accurately on this map
The Mercator projection is a cylindrical map projection presented by the Belgian geographer and cartographer Gerardus Mercator, in 1569. It became the standard map projection for nautical purposes because of its ability to represent lines of constant course, known as rhumb lines or loxodromes, as straight segments
Nautical chart
Such a map is commonly known as a nautical chart.
water depths and navigational routes
Water depth.
Marine Chart or Nautical Chart.
See related link for a star map
according to my map, its about 3 inches
navigation on water.
Use a chart not a map. WGS 84 is probably the best datum
it's called a chart. Nautical maps are referred to as "Charts".
In this context, a minute is 1/60 of a degree.
The word nautical miles are frequently used by mariners, seafarers, a measure of distance on a geographic map and standard of measure S.I.