A polar or azimuthal projection is centered around the pole or a single point. A cylindrical projection, such as the Mercator shows the grid as a flat rectangle and is best for direction. The Goode s projection uses mathematical curves to show the whole world. It maps the area of land masses correctly but distorts their shape. Earth s rotation causes differences in time and date.
Local time is sun time as recorded on a sun dial.
For convenience, we use standard time which divides the world into 24 time zones . Fifteen degrees of longitude equals one hour of clock time. When crossing this line westward, the calendar is moved forward to the nextday. When crossing the line eastward, the calendar is moved back to the previous day. The plane of this orbit is called the plane of the ecliptic .