Planar

Planarity and planarity refers mutatis mutandis, the spatial arrangement ( ie, in three-dimensional space ) of points in a plane; the points are then plan ( in mathematics: coplanar ).

Two flat surfaces that are parallel hot, plane-parallel.

Disambiguation plan - planar

In German usage is flat, never planar, as in the English, from which it is borrowed in some expressions like screens, lenses ( Gaussian doublet or Planarobjektiv ) or other optical equipment. The term plan is " in an area " planar stands for " planar " in graph theory ( planar graph ), and for " in the ( low ) level ( flat landscape ) " in the geosciences ( lowland stage).

Measurement

Planarity refers to the surface quality; see flatness in general and surface roughness at specific accuracy
An area in the building is flat if it is sufficiently flat; see grading
Align is a manufacturing method to form a work plan.

Optics

In optical lenses planarity is a quality to what extent the cut approaches the ideal curve. For the flat surfaces of prisms, lenses or mirrors to use the expression plane surface.

A plane-parallel glass body is called a plane plate.