bjc social studies tutorials...•on the bjc you will be asked to find the real distance between two...
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Suggested Social Studies texts
Mapping and Map Related Skills (part2)
Scales
• Maps are a visual representation of a large area of land so scales are an important component
• A scale on a map indicates the relationship between a distance on a map to the actual distance on the ground
• There are a few types of scales, Word scales, linear scales and fractional scales
• Scales are usually located in the legend box of a map
Linear Scales
• Linear Scales uses a line with separations marked by smaller intersecting lines, similar to a ruler.
• One side of the scale represents the distance on the map, while the other side represents the true distances of objects in real life.
• One benefit of using a linear scale is that it is a straight forward, easy way to determine scale.
• Secondly, if a map’s size is enlarged or decreased, the scale is also enlarged or reduced, meaning that it is still accurate.
• Linear scales are also referred to as bar scales
Word Scales
• The verbal method of depicting scale simply uses words to describe the ratio between the map's scale and the real world.
• .
Fractional Scale
• The fractional method for portraying the scale of a map uses a representative fraction to describe the ratio between the map and the real world.
• This can be shown as 1:50,000 or 1/50,000. Here such a scale means that 1 unit of measurement on the map is equal to 50,000 of the same unit on the ground
• This means that 1 inch on the map represents 50,000 inches in the real world, 1 foot on the map represents 50,000 feet on the map, and so forth.
Using Scales
• As mentioned before scales are used to calculate the exact real life distance between two locations
• You should have a ruler and a pencil to measure the distance on the map and mark it
• On the BJC you will be asked to find the real distance between two locations found on a map.
• For ach type of scale the same general idea applies when measuring
Measuring Using Linear Scale
• By measuring the distance between two objects on a map and then referring to the graphic scale, it is easy to calculate the actual distance between those same items.
• Use you ruler to measure the actual distance between the two distances
• Mark the spot on your ruler• Then line the ruler up to the linear scale,• What ever measurement your mark lines up with
on the scale will be your actual distance
Measuring Using a Word Scale
• Calculating scale on a map using the verbal method is easy.
• Use your ruler measure the distance on the map
• Then follow the verbal directions to calculate the actual distance.
• For example, a map might say something like, “one inch equals one hundred and fifty miles
• If your measured distance is 6 inches
• You would simply multiply 6 by 150, your answer will be 900 miles.
Measuring using Fractional Scale
• If the fractional scale is given as 1:1,000,000
• (1 cm to 10 km)
• You would again measure with your ruler and use the ratio to find the actual distance
• If you measured distance is 15 cm
• You would multiply 15 by 10, your answer would be 150km
Location
• The earth is divided into three parts, the top is the North Pole, the middle is the Equator and the bottom is the South Pole.
• The top is called the northern Hemisphere degrees of 0-90 North
• The bottom is called the Southern Hemisphere degrees of 0-90 South
• These are in turn divided into a grid of latitude and longitude lines, which are used to find locations on maps
Latitude
• Latitude lines run horizontally ,parallel with the equator and specify the north to south coordinates of a location
• Latitude lines of significance include
– Tropic of Cancer
– Arctic Circle
– Tropic of Capricorn
– Antarctic Circle
• Longitude lines run vertically but specify the east to west coordinates of a location
• Longitude lines (also called meridians) are used to tell time as well to find locations
• The Greenwich meridian is considered the universal starting point for lines of longitude at 0⁰
• The international date line is an imaginary line located on the opposite side of the earth to the Greenwich Meridian and is used to differentiate one day from the other
• The longitude degree of the IDL is 180⁰.
• Latitude lines and longitude lines are very important when it comes to locating countries and cities
• As the world is broken down into a grid of longitude and latitude lines which all carry degree measurements, which become coordinates
• Longitude lines are given in degrees of East or West in relation to the Greenwich meridian.
• Latitude lines are given in degrees of North to west in relation to the Equator.
• We use these coordinates to locate places such as Grand Bahama Island is 26.6500° N, 78.3167° W
What to expect in the next lesson?
- Types of Maps, Maps of The Bahamas and World
Extra Work for BJC Students
For extra practice, download past papers from www.TheStudentShed.com