b.Class Notes #4

• Maps' function shifted from a tool that provided location reference to a tool used by geographers to communicate complex geographic phenomena.
• Scientific method of transferring location on Earth's surface to a flat map is called a projection.
• Earth's spherical shape causes distortion when drawing it on a flat piece of paper.
• Four types of distortion are:
1. Shape of an area can be distorted.
2. Distance between points may become either increased or decreased.
3. Relative size of different areas can be altered.
4. Direction between points can be distorted.
• Geographic grid is a system of imaginary arcs drawn in a grid pattern on Earth's surface.
• Meridians are arcs drawn between North and South poles (vertical).
• 0० ( prime meridian, Greenwich) - 180० east/ west longitude.
• Parallels are arcs drawn parallel to the equator line (horizontal)
• 0० ( equator) - 90० North or South latitude.
• Points on Earth's surface can be communicated by referencing latitude and longitude intersection.
• Further accuracy can be achieved by dividing each degree into 60 minutes, and each minute into 60 seconds.
• Earth as a sphere divided into 360० longitude.
• Divide into 360० by 24 time zones (one for each hour of day) equals 15 ∴ each band of 15० longitude is assigned to a standard time zone.
• Greenwich Mean Time (GMT) is:
• Located at the prime meridian.
• Passes through Royal Observatory at Greenwich.
• master reference time for all points on Earth.