Problem 1 Problem: If it is noon where you are, would it be before or after noon for someone that is east of you? ◦ After noon Recall, the sun rises in the east and sets in the west ◦ As you look down from the north pole, the earth would rotate counterclockwise ◦ If the sun is just beginning to rise in California, then the sun would be near noon in New York, so… ◦ As you travel east, time becomes later
Standard Time To simplify things, 24 zones of standard time have been established internationally As you move from one time zone to the next adjacent time zone, standard time changes by one hour
Time Zone Calculations Standard time: 12:00 AM to 11:59 AM 12:00 PM to 11:59 PM Military time/24-hour clock: 00:00 to 23:59 ◦ No AM or PM is needed Regular time and military time…how do you convert? ◦ If it’s before 1:00 PM, no need to convert ◦ If it’s 1:00 PM or later, +12 to get military time e.g., 1:01 PM + 12 = 13:01 military time 6:50 PM + 12 = 18:50
Time Zone Calculations, cont. Greenwich Mean Time (GMT): ◦ Runs through Greenwich, UK…recall which is 0 ° longitude ◦ Established in 1884 (height of British naval dominance) ◦ 24-hour clock known today as the Universal Time Coordinate (UTC) or Zulu time ◦ Used as a reference If you know the current UTC time, you can figure out what time it is anywhere in the world
International Date Line Located in the middle of the Pacific Ocean near 180 ° longitude. If you cross the IDL from east to west, then it’s the next day (+1 day) If you cross the IDL from west to east, then it’s the previous day (-1 day)
Daylight Savings Time Used primarily in the U.S. to add an “extra” hour of daylight in the afternoon during spring/summer Just remember, “Spring forward and Fall back” Problem Part I, question 4: ◦ Convert daylight savings time in KC to standard time by subtracting one hour, then continue to find the day/time in Ecuador
Graphic Scales The distance on a map related to ground distance Length on a map can be compared to the graphic scale to find true ground distance Remains accurate if the map is reduced/enlarged
Fractional Scales Map distance related to true ground distance in the form of a fraction or ratio ◦ e.g. 1/24,000 or 1:24,000 This is to say that “one unit on the map is equal to 24,000 units on the ground” Need a calculator and ruler If map scale is enlarged or reduced, fractional scales will be inaccurate.