To measure linear distance using a linear scale bar on a map or diagram, you typically use a ruler to determine the relationship between a distance on the scale bar and the actual distance it represents in the real world.
Understanding the Linear Scale Bar
A linear scale bar is a visual representation of the map's scale. It shows a specific length on the map and indicates what real-world distance that length corresponds to.
As highlighted in the reference, when using a scale bar:
- You measure the scale bar with a ruler.
- For instance, the reference notes that on a particular scale bar, "zero to one thousand meters is the same as eight centimeters on the ruler". This establishes the fundamental relationship: 8 cm on the map equals 1000 meters in reality.
This measured relationship is your key to converting distances measured on the map into real-world distances.
Steps to Measure Distance Using a Scale Bar
Here’s how you can use the measured relationship to find distances:
- Measure the Scale Bar: Use a standard ruler to measure the physical length of the scale bar on the map. Note the real-world distance that this measured length represents (e.g., 8 cm = 1000 meters).
- Measure the Object or Route: Using the same ruler, measure the length of the specific object, route, or distance you want to determine on the map.
- Calculate the Real-World Distance: Use the relationship established in step 1 to calculate the real-world distance corresponding to the length measured in step 2.
Example Calculation
Let's use the example from the reference: 8 cm on the map = 1000 meters in reality.
- Relationship: 1 cm on the map = (1000 meters / 8 cm) = 125 meters
- If you measure an object on the map and it is 4 cm long:
- Real-world length = 4 cm * 125 meters/cm = 500 meters
- If you measure a route on the map and it is 16 cm long:
- Real-world length = 16 cm * 125 meters/cm = 2000 meters
By measuring the scale bar with your ruler, you effectively calibrate your ruler for that specific map, allowing you to measure any distance on the map and convert it to its real-world equivalent.
