How did aerial photography change mapmaking during the world wars?

Aerial photography revolutionized mapmaking during the world wars by enabling the rapid, large-scale documentation of terrain that was previously unmapped or inaccessible. Before World War II, less than 10 percent of the world was mapped in sufficient detail for basic pilot charts.12

The most significant development during this period was the trimetrogon method, which utilized three wide-angle cameras to photograph terrain from horizon to horizon across the line of flight. This allowed for the efficient coverage of vast, remote areas, providing the essential data needed to create World Aeronautical Charts.31

While aerial photographs are not maps themselves due to inherent distortions, they served as vital map substitutes. Cartographers addressed these distortions by using overlapping photographs to create a framework of identified points, which allowed them to scale and orient the imagery. This era laid the foundation for modern photogrammetry, transitioning from simple reconnaissance to sophisticated techniques that eventually utilized plotting instruments to derive accurate elevations and contours from three-dimensional models.342