Climate maps use colors and symbols to show the difference in average weather conditions over large areas. Humidity maps often use shades of green to show average precipitation in areas, or shades of brown to denote areas with little precipitation. Climate maps may also use shades of red to denote areas with high average temperatures and shades of blue to white to denote areas with average temperatures that are extremely low. By consulting the key that explains temperature ranges represented by the different colors, you can determine the average temperature in different areas.
Physical maps show the physical elements in an area, such as the presence of lakes and rivers, represented as areas of blue by the keys on physical maps. These kinds of maps also include mountains and areas of high elevation, generally represented by areas of brown by most keys. On physical map keys, you can also find symbols for caves, forests, swamp areas and other physical features in an area, denoted by small shapes that represent these features.
Political maps show boarders between governmental areas, such as countries, states, counties, cities and towns. Political maps use small dots to represent cities, or stars to denote capital cities. Some political maps use dots of different sizes to denote cities with different population levels. Cities use small area political maps to show property lines between people's homes and city properties.
Road maps use lines to denote roads, railroads, highways and city streets. These maps use different lines to show the differences between each of these kinds of roads, such as thick lines that represent highways and thinner lines to represent smaller city roads. Road maps provide an easy reference to help people navigate roads and determine directions on driving trips. Road maps also include important travel information, such as symbols for airports, restaurants, hotels and tourist locations.
Topographical maps use lines known as contour lines to denote a rise or fall in elevation. Contour lines show areas of equal elevation. When several of these lines on a topographical map are very close together, it denotes a steep increase or decrease in elevation, while lines that are farther apart denote an area that is more flat. The map key on a topographical map lists an elevation, usually in feet, of the regular increase or decrease in elevation that multiple contour lines represent.