What does Ground Sample Distance (GSD) indicate in remote sensing?

Ground Sample Distance (GSD) is a critical concept in remote sensing, representing the distance between the centers of two adjacent pixels on the ground. This measurement directly relates to the spatial resolution of the imaging system. A smaller GSD indicates higher resolution, meaning that smaller features on the ground can be distinguished in the resulting images.

Understanding GSD is fundamental because it affects the detail and clarity of the imagery obtained from remote sensing techniques. For example, in applications like urban planning or forestry, knowing the GSD allows users to assess how accurately they can view and analyze the landscape.

The other choices address different aspects of remote sensing but do not define GSD accurately. While the area covered by a satellite (the first choice) refers to the overall reach of the sensor’s capabilities, it does not pertain to the pixel-level detail that GSD measures. The height of the satellite (the third choice) provides context about the satellite's orbit but does not convey any information about ground pixel spacing. Lastly, the speed of satellite rotation (the fourth choice) is unrelated to pixel resolution or ground sampling, focusing instead on the satellite's operational dynamics.