In plane sailing, d_lat and m_lat calculations are used to determine the change in latitude (d_lat) and the mean latitude (m_lat) during a specific course and distance sailed. Let's break it down:
Change in Latitude (d_lat): This calculation helps determine the change in latitude after sailing a specific distance on a given course. It accounts for the curvature of the Earth. The formula used for d_lat is:
d_lat = (Distance x sin(Course))/60
Distance: The distance sailed in nautical miles.
Course: The true course (bearing) in degrees.
The result is divided by 60 to convert from nautical miles to minutes of latitude.
Mean Latitude (m_lat): The mean latitude is the average of the initial and final latitudes after sailing a specific distance on a given course. It's useful for simplifying calculations involving meridional parts and departure. The formula used for m_lat is:
m_lat = (Initial Latitude + Final Latitude) / 2
Initial Latitude: The latitude at the starting point.
Final Latitude: The latitude at the destination point.
The mean latitude is calculated by adding the initial and final latitudes and then dividing the sum by 2.
These calculations are fundamental in plane sailing for estimating the ship's position and determining the necessary adjustments in course and latitude. By understanding and using d_lat and m_lat, navigators can accurately plot their course on a chart and maintain a reliable track of their position.
