![]() ![]() The representative fraction scale has two advantages over the other two types of scale. It may state “1 cm ⫽ 100 km.” If you are not familiar with centimeters or kilometers, you will not be able to relate the scale used on the map to actual distances on the Earth’s surface. Let’s say that you are not familiar with the metric system, and the map you are looking at has both the linear and verbal scales in metric notation. A representative fraction (RF) scale is the most useful, since it does not require prior knowledge of any particular distance measuring system. That 1 inch on the map would actually equal 100 miles on the Earth’s surface. For example, it may say: “One inch equals 100 miles.” This means Verbal scale is simply a sentence that states the relationship of distances on the map to actual distances on the Earth. For example, if you take a ruler and measure the distance between two spacing ticks on the bar line, this distance will help you understand the actual distance between places on the Earth. The spacing between the markings indicates actual Earth distances. The linear or bar scale is a horizontal line drawn with markings placed at specific intervals indicating distances. There are three types of scales, and most maps made today have all three types: a. You will usually find scale in the legend or key box. Scale helps in understanding the relationship between map distances and actual Earth distances. No other place on Earth has this geographic coordinate. This geographic coordinate is unique to Los Angeles. An example would be the geographic coordinates for the city of Los Angeles, California: 34 degrees north (of the equator) and 118 degrees west (of the prime meridian). At the intersection points of these lines, you will find geographic coordinates. Parallels of latitude lines run east to west across maps, while meridians of longitude lines go north to south. The geographic grid is the “netting” that consists of latitude and longitude lines. Location refers to the geographic grid that is usually overlaid on every map. However, today most cartographers (mapmakers) omit this symbol, assuming that the map viewer knows that the top of the map is north, the bottom is south, the left-hand side is west, and the right-hand side is east. Direction is usually indicated by placing a compass rosette on the map showing where the major cardinal points are: north, south, east, and west. In addition, the legend box contains vital information useful in decoding other map markings. The color blue is almost always used to indicate water-oceans, seas, lakes, streams, or rivers. However, on most maps, the color green indicates low elevation. For example, most students who see the color green on a map associate it with vegetation, such as trees, grass, or forests. A legend or key box-usually placed at the bottom of a map- decodes all the colors and symbols used on the map. For example, if a map shows a country called the Soviet Union, you know that the map was printed before 1991. Without a date on a map, you need to look for other clues, such as political boundaries and countries. A date tells the map viewer how current the information is. ![]() A name or title prevents confusion by clearly stating what it is you are looking at. Every map should have several essential bits of information. A Guide to Map Reading Prepared by Peter Konovnitzine Chaffey CollegeĪps can be compared to computers-they contain a lot of information that needs to be viewed, interpreted, and decoded. ![]()
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