Road maps use symbols to convey clear visual information. Symbols are used to represent roads and highways, places of interest, state capitals, and rivers. According to Things Travelers Need to Know, "There is no explicit agreement between cartographers on the marks and signs that are used to represent real world features on maps," which means you have to do a little investigating to read the symbols on each road map you use.
Find the map's legend. Almost every map includes a small box showing each symbol and telling what it represents. If you cannot find a legend on the same page as the map you are viewing, look on the front cover, back cover, or initial pages of the atlas, according to Things Travelers Need to Know.
Locate the map's scale. Maps include a scale showing the proportional relationship between the map and real life. The scale will show how many feet or miles an inch on the map represents.
Locate the cardinal directions. These could be displayed on a compass rose, with many points, or a pair of perpendicular lines, with just four points showing north, south, east, and west. This helps you understand the orientation of the map.
Recognise that various coloured lines have different meanings. Blue lines are usually rivers or waterways. According to the Boy Scout Trail website, black lines designate man-made roadways and red lines represent primary highways. The thickness of the line also matters, as larger roadways and rivers will be represented with thicker lines. Also, railways are shown with lines with small lines crossing them, resembling a track.
Look at the pictorial symbols for points of interest. These can usually be figured out with a common reasoning. For example, a little tent represents a campsite and an aeroplane represents an airport. Some may be less easily understood, such as a circled letter "I" for information. To review some common symbols, visit the Cartographic Symbols & Map Symbols Library.
Find large bodies of water by looking for blue shapes. The size of the shape correlates to the size of the body of water. If it's a significant body of water, the name will be included.
Locate capitals and large cities by looking for stars and dots. Often, a star will represent the capital. The size of the dots by city names will correlate to how large the city is. Sometimes, instead of using dots, a map will suggest city size by changing the font size of city names.
Recognise that background colour might be significant. On some maps, large natural areas will be blocked off in green. Large government-owed properties, such as military bases, will be blocked in another colour.
Look for contoured lines, which represent changes in altitude (height above sea level). Not all road maps include these, but if you see them, it is helpful to know what they mean. If contoured lines are very close together, the altitude greatly increases in this area, such as with a mountain or plateau. Lines that are spread out represent flatter ground.
Visit the Boy Scout Map Symbols Online Test to test your familiarity with common symbols.