What defines the relationship between distance on a map and actual distance on Earth?

The relationship between distance on a map and actual distance on Earth is defined by map scale. Map scale provides a ratio or proportion that translates real-world distances to distances represented on the map. For instance, if a map scale indicates that one inch on the map corresponds to one mile in the real world, this allows users to measure distances accurately using the map.

Map scales can be represented in various formats, including numerical ratios (e.g., 1:100,000), written scales (like "one inch equals one mile"), or graphic scales (a visual representation showing distances). However, the overarching term that encompasses all these formats and defines the relationship itself is "map scale."

Understanding map scale is crucial for effective navigation and geographical analysis, as it helps users interpret and utilize maps correctly to estimate real-world distances and areas based on their representations.