视线传播指的是电磁射线沿直线传播的行为。射线或者波，遇到障碍物时偏离原路径或者被反射，而不能继续沿地平线或者绕过障碍物传播。除此之外，物质材料依照波的能量的不同对射线进行不同的散射。

Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line. The rays or waves may be diffracted, refracted, reflected, or absorbed by atmosphere and obstructions with material and generally cannot travel over the horizon or behind obstacles.