Which of the following is not a type of distance measurement mentioned in surveying?

In surveying, various methods are employed to measure distances accurately, and each of the methods listed plays a significant role in the field. Direct measurement involves physically measuring the distance using rulers or tapes. Tachyometric measurement employs theodolites with specialized techniques to compute distances from angles, while stadia measurement, which is a form of tachymetric measurement, utilizes a telescope with a horizontal crosshair to determine distances based on angular readings.

Instrumental measurement is indeed a term related to surveying, but it's more of an overarching category, rather than a distinct method of distance measurement. It refers generally to the use of various instruments, which include those employed for direct, tachymetric, and stadia methods. Therefore, since the question specifically seeks a type of distance measurement and not a general category of measurements or methodologies, it is appropriate to classify instrumental measurement as not fitting the criteria of a specific distance measurement type listed in the question.