Retrieving "Leveling Instrument" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Surveying

   Linked via "leveling instruments"

   Surveying inherently operates within a defined spatial reference system. Since the Earth is not a perfect sphere, the choice between utilizing a spherical model (leading to Geographic Latitude, $\phi_g$) or an ellipsoidal model (leading to Geodetic Latitude, $\phi$) is paramount for accurate fieldwork.
   Geodetic latitude ($\phi$), defined by the normal to the [reference ellipsoid](/entries/r…