What defines the positional accuracy of a feature in GNSS?

The positional accuracy of a feature in Global Navigation Satellite Systems (GNSS) is primarily defined by how closely the reported location of that feature aligns with its true geographic position. This is evaluated through various means, including error measurement techniques, where the difference between the known true location and the GNSS-derived location is quantified. Accuracy is important because it directly affects the reliability of the data collected for applications such as mapping, surveying, and navigation.

The other options do not directly measure positional accuracy. For instance, the distance to the nearest feature can provide contextual information about proximity but does not indicate how accurately the feature's location is represented. The speed of signal transition refers to the signal transfer between satellites and receivers, which is related to timing and is not a measure of position accuracy. Lastly, while the number of satellites in view can influence the quality of the GNSS signal and can enhance accuracy, it is not an inherent measure of how close a reported position is to its actual location. Therefore, the closeness of the feature location to the true position is the most appropriate definition of positional accuracy in this context.