All points on the map have two coordinates: width and longitude which are counted from the equator and a zero meridian respectively. As Earth has the sphere form, the width and longitude are angular sizes.
Instruction
1. Width is a corner between the plane in which the equator, and the line drawn perpendicular to the Earth's surface lies. Thus, on the equator this corner is equal 0 degrees, and on poles - 90 degrees. Longitude is a corner between the plane of a zero meridian and the plane of a meridian which passes through the surface point interesting us.
2. The equator divides the globe into two half: northern and southern. Parallel to the equator apply special lines on the card and the globe - parallels. All points located above the equator have northern latitude, and those which are lower than the equator - southern. Perpendicular to the equator other lines - meridians are located. A meridian take the line passing through laboratory in Greenwich for a zero reference point. All points which are located to the east of a zero meridian have east longitude, and those which to the west of a zero meridian - western.
3. For determination of coordinates of a point use a frame from applied on it with minute and second-degree scales. These coordinates put for the objects which are strongly removed from each other into practice.