Longitude and Standard Time. Other Measures of Absolute Location. Relative Location

A woman from Los Angeles took a business trip to Japan. Upon arriving, she called her child in Los Angeles and explained that it was already Tuesday morning in Tokyo while it was still Monday afternoon in California. "Did the Raiders win Monday Night Football tonight?" replied the child. Although the hotel television system provided up-to-the-minute sports scores from around the world, the woman could not answer the question. Why not?

The answer to this question hinges on the relationship between longitude and standard time (Box 1-1). The earth completes a 360° rotation on its axis every twenty-four hours; hence, it rotates 15° per hour. Westward travelers set their watches back one hour for every 15° of longitude crossed. Travelers from Boston to San Francisco set their watches back three hours. Eastward travelers advance their watches. When it is noon in Boston, it is 9:00 a.m. in San Francisco.

In general, why don't you lose a day when making a trip around the world and setting your watch back twenty-four times? In order to correct this problem, the International Date Line has been established by international agreement. The International Date Line for the most part follows the 180° meridian, but it is adjusted in order to avoid dividing land areas or political units.

People crossing the International Date Line from west to east set their watches back twenty-four hours, while westward travelers set theirs ahead twenty-four hours. When it is Sunday afternoon in Los Angeles, it is Monday morning in Australia and East Asia. A live broadcast of a Monday night football game in the United States would be shown Tuesday morning in Japan.

Other Measures of Absolute Location. Would you use latitude and longitude to tell a friend where you live? Why not? Instead of reporting latitude and longitude, people use street addresses and other information to determine absolute location within communities.

Postal zone codes, such as the ZIP codes used in the United States, also fix absolute location. In recent years, the U.S. Postal Service's controversial decision to implement nine-digit as opposed to five-digit ZIP codes was intended to expedite mail delivery by providing more precise locational information to postal workers. Critics of the nine-digit system claim that the extra digits confuse letter writers while failing to improve the speed and accuracy of mail delivery.

Similar systems in which absolute locations are identified through a combination of letters and numerals are in use in many other countries. The use of ZIP codes and other symbols to determine absolute location is called geocoding.

Relative Location. Statements of relative location identify locations on the basis of comparison with other locations. Statements such as "I live two miles from the beach" or "I live five blocks east of the campus" are statements of relative location. In ordinary conversation, we frequently use words and phrases such as "downtown," "across the tracks," "uphill," and "downstream" in order to provide information about relative location.

Direction and distance are the two key components of relative location. If we know the location of one point, we can fix the location of any other point by knowing its direction and distance from the original point.

Directional information, like location itself, can be relative as well as absolute. We have seen how the cardinal, or absolute, directions are defined by the earth's rotation on its axis. In ordinary conversation, however, we often use language that identifies direction relative to our own location. Californians often refer to events 'back east." while New Englanders discuss events "out west." The use of the terms "back" and "out" reflects American history, in which Europeans moved westward across the North American continent.

Many Americans describe places as "up north" or "down south." These terms originated from our custom of orienting maps with north at the top and south at the bottom. This custom also has influenced the use of directional terms to describe larger areas. Residents of New York City call the rest of the Empire State "upstate New York." Similarly, residents of the Chicago area refer to the rest of their state as "downstate Illinois."

Americans often think of Saudi Arabia. Israel, and Jordan as part of the "Near East" or "Middle East" and China. Japan, and Korea as part of the "Far East." These and other regional labels refer to relative direction from Europe. The Chinese themselves, on the other hand, would speak of their country as "the Middle Kingdom," emphasizing China's view of itself as the center of civilization. In order to eliminate these biases involving relative location, it has become customary to use such terms as "Southwest Asia" to describe the Arabian peninsula and "East Asia" to describe China and its neighbors.