The author has another blanket statement:
“7) Surveyors, engineers and architects are never required to factor the supposed curvature of the Earth into their projects. Canals, railways, bridges and tunnels for example are always cut and laid horizontally, often over hundreds of miles without any allowance for curvature.”
This could be as simple as saying an aerospace engineer has to factor in the curvature of the Earth when planning a rocket launch to place a satellite in orbit. Since I was just posting about Surveying and Leveling, I know that they do factor in the curvature of the Earth for projects with the equation:
An engineer devising a GPS location also considers the curvature of the Earth. Most structures are built small enough not to consider Earth’s curvature (for example, my house). A very large bridge or airplane hangar might have to consider the Earth’s curvature. Anyway, here is an structural engineer saying how he considers the Earth’s curvature for span bridges because he wants the main supports parallel to the direction of gravity and not parallel to each other. That same post on reddit has other engineers talking about the importance of considering it for building railways and microwave communication systems.