Answer following about surveying, the task of positioning points on Earth, for 10 points each.
[10h] Modern surveying is typically done with a total station, which is one of these devices equipped with an electronic distance measurement system. These devices consist of a mounted telescope used to measure angles.
ANSWER: theodolites [accept total station theodolites]
[10m] Theodolites are commonly used to perform levelling, the measurement of height relative to one of these points of references. The mean sea level is commonly used as one of these points for altitude.
ANSWER: datums [reject “data”] (The plural of “datum” is “datums” in this context.)
[10e] Mean sea level is preferred over instantaneous sea level as a vertical datum in part due to these phenomena. The gravity of the Sun and Moon cause these variations in sea surface height.
ANSWER: tides
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