Overview
This lesson introduces map scales and explains how to calculate real-world distances using a given scale, with a focus on proper measurement and unit conversions.
Understanding Map Scales
- Map scales show the ratio of a length on the map to the actual distance in real life (e.g., 1:50,000).
- A scale of 1:50,000 means 1 unit on the map equals 50,000 of the same units in reality.
- Measurement accuracy depends on consistent zoom and device settings; use the same setup as the instructor or official materials.
Calculating Real-World Distance
- To find the real-world distance: measure the map distance, then multiply by the scale factor.
- Example: If the map distance between two points is 4.2 cm and the scale is 1:50,000, the real distance = 4.2 × 50,000 = 210,000 cm.
- It is often more practical to convert the result to kilometers or meters.
Converting Units
- Length units commonly used: kilometers (km), meters (m), centimeters (cm), and millimeters (mm).
- Conversion steps:
- To go from cm to km, divide by 100 (to get meters), then divide by 1,000 (to get kilometers).
- Example: 210,000 cm ÷ 100 ÷ 1,000 = 2.1 km.
Example Problems
- Example 1: Map distance = 4.2 cm; real-world distance = 2.1 km after conversion.
- Example 2: Map distance = 13.7 cm; real-world distance = 6.85 km after conversion.
Key Terms & Definitions
- Scale — The ratio of map distance to real-life distance.
- Map distance — The length measured between two points on a map.
- Real-world distance — The actual distance between two locations in reality.
- Conversion — The process of changing measurements from one unit (e.g., cm) to another (e.g., km).
Action Items / Next Steps
- Review conversion factors between cm, m, and km.
- Prepare for future lessons covering different types of map scale questions.