What type of data is primarily used to create a nautical chart?

The primary data used to create a nautical chart includes information related to the geoid, which is the shape of the Earth's surface as it corresponds to mean sea level. This data is foundational because it provides information about the Earth's gravitational field and helps in establishing accurate vertical datums. Nautical charts are designed to represent the positions of physical features, depths of water, and the contours of the seabed, all of which rely on precise geodetic measurements. The determination of the geoid allows hydrographic surveyors to accurately depict these features on nautical charts, ensuring safe navigation for vessels.

While temperature measurements, salinity levels, and wind speed are important in understanding oceanographic conditions and can influence navigation, they do not directly contribute to the creation of nautical charts. Nautical charts focus primarily on spatial and physical characteristics of marine environments, which are defined by geodetic data.