You use scale on a map or plan to calculate the real-world distance between two places by measuring the distance on the map and then converting it using the map's scale.
Here's a breakdown of the process:
Steps to Calculate Distance Using Scale
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Understand the Scale: The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. It can be represented in several ways:
- Representative Fraction (RF): Expressed as a ratio, such as 1:25,000. This means 1 unit on the map represents 25,000 units on the ground.
- Verbal Scale: Expressed in words, such as "1 centimeter equals 1 kilometer."
- Graphical Scale (Scale Bar): A line or bar drawn on the map that is divided into segments representing distances on the ground.
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Measure the Distance on the Map: Use a ruler to measure the distance between the two places on the map. Ensure you're using the appropriate units (e.g., centimeters, inches).
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Convert the Map Distance to Real-World Distance: This is where you apply the scale. The method depends on the type of scale:
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Representative Fraction (RF):
- Example: Map distance = 5 cm, Scale = 1:25,000
- Real-world distance = Map distance Scale factor = 5 cm 25,000 = 125,000 cm
- Convert to a more usable unit (e.g., kilometers): 125,000 cm = 1.25 km
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Verbal Scale:
- Example: Map distance = 7 cm, Scale = "1 cm equals 1 km"
- Real-world distance = Map distance Scale value = 7 cm 1 km/cm = 7 km
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Graphical Scale:
- Use a ruler to measure the length of the map distance.
- Compare this length to the graphical scale bar on the map.
- Read off the corresponding real-world distance directly from the scale bar.
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Example
Let's say the distance between two cities on a map is 8 centimeters, and the map scale is 1:100,000.
- Map Distance: 8 cm
- Scale: 1:100,000
- Calculation: Real-world distance = 8 cm * 100,000 = 800,000 cm
- Conversion: 800,000 cm = 8,000 meters = 8 kilometers
Therefore, the actual distance between the two cities is 8 kilometers.
