Conversion of Coordinates

In the logbook itself, latitude and longitude are measured with decimals (i.e. 120.34 degrees North). However, Google maps - the program which we will be using to actually plot these coordinates to form a comprehensive route that the ship took - uses coordinates measured in degrees, minutes, and seconds. To do this, one must understand the method used to convert between the two forms of coordinate notation.

For instance, the angle 28° 30'15" (the symbol ' denoting minutes and " denoting seconds) is equal to 28.504167 degrees.

To convert from 28° 30'15"", the equation used is 28+(30*1/60)+(15*1/60*1/60). Each minute is 1/60 of a degree, and each second is 1/60 of a minute, or 1/60 of 1/60 of a degree. 

In order to convert in the opposite direction (minutes and seconds to decimals), we take the decimal alone:0.504167, and multiply it by 60: 0.504167 * 60 = 30.25. We then take the decimal of this number (0.25) and multiply it by 60 as well: 0.25 * 60 = 15. As a result we are left with 28° 30'15"