For a diagonal metric tensor , where
is the Kronecker delta,
the scale factor for a parametrization
,
, ..., is defined by
|
(1)
| |||
|
(2)
|
The line element (first fundamental form) is then given by
|
(3)
| |||
|
(4)
|
The scale factor appears in vector derivatives of coordinates in curvilinear coordinates.