Assertion: triangulation | /r/ObjectUse | used by greek
Facets:
value: at a very early date
type: TEMPORAL
value: with crude sighting devices
type: OTHER
Source sentences:
text: Triangulation was used by the ancient Egyptians, Greeks, and other peoples at a very early date, with crude sighting devices that were improved into the diopter, or dioptra (an early theodolite), and were described in the 1st century ad by Heron of Alexandria.