What does each line on the grid map represent in terms of city blocks?

Each line on the grid map represents 4 city blocks. In urban planning and architecture, grid maps are commonly used to denote street layouts and city blocks. A standard measurement often employed in many cities, including Chicago, is that one block is equal to approximately 1/16th of a mile. By understanding that a typical grid block usually spans a certain distance, the representation of 4 blocks between grid lines becomes a useful tool for navigating and conceptualizing distances within the city.

The choice indicating 4 city blocks reflects this established measurement, helping architects, planners, and the public visualize and interpret the size of geographical areas. By knowing that each line signifies 4 blocks, users can accurately estimate distances and navigate the urban landscape effectively.