planspegel
Planspegel is a term used in surveying, cartography, and architecture to denote a fixed reference marker on a plan or map that ties the drawing to real-world measurements and orientation. It functions as an anchor for interpreting, reproducing, and aligning plan data with field measurements and other drawings.
In practice, a planspegel may indicate the scale of the drawing, the coordinate grid, and the directional
The concept is related to, but distinct from, physical benchmarks or control points installed in the field.
See also: benchmark, control point, reference mark, scale bar, coordinate system, planimetry.