E PRINCIPLES AN PRACTICE or NAVIGATION
Change of Position on the Earth's surface when sailing between any two positions on the earth's surface, a knowledge of the necessary change in latitude and longitude is essential
this information is described by the 'Difference of Latitude. d. lat.) Differe Lol ude" g), betwee two positions positions on the earth's surface is the The d. lat, between any two thie two parallels arc of a meridian which is contained between in latitude which pass through the two pos ons. This is two position igure 1.4. From the figure it can be seen that if the the numencal have latitudes of the same name then the d, lat will be the smaller difference between the two latitudes Le, the greater minus sum If the latitudes are of different name then the d. lat will of the two latitudes. WE Equator through A aa of ude bb parallel of latitude B ec' o latitude through Latitude B arc ab d, lat, between A and B Latitude A d lat between A and C atitude A t Latitude C are act d lat between B and C- Latitude B t Latitude C bc D. lat. is according to the direction travelled, North or named The between any two positions on the earth's surface is the lesser arc equator contained between the two meridians which pass through the two positions. This is illustrated in Figure I s From the figure it can be seen that if the two positions are on the same side of the Greenwich meridian then the d. long, will be