Curvilinear Coordinate Systems are either Oblique Coordinate Systems or are Coordinate Systems in which atleast One of the Coordinate Axes is Not a Straight Line.
Unlike Cartesian Coordinate Systems where the Nomenclature of Coordinates / Coordinate Axes are fixed, the Nomenclature of Coordinates / Coordinate Axes in Curvilinear Coordinate Systems vary from one to another depending on the Type of the Curvilinear Coordinate Systems.
Curvilinear Coordinate Systems without a well defined Origin are called Affine Coordinate Systems.
Any Curvilinear Coordinate System of a given Dimension (with a well defined Origin) has a one to one correspondence with the Cartesian Coordinate System of similar Dimension.
That means any Coordinate Location given by the Coordinates of the Curvilinear Coordinate System of a given Dimension can be converted to
a Coordinate Location given by the Coordinates of the Cartesian Coordinate System of similar Dimension
and vice versa.
For example, given a Coordinate Location \((u, v, w)\) in a 3 Dimensional Curvilinear Coordinate System having Coordinate Axes \(U\) , \(V\) and \(W\), the Coordinate
Location in 3 Dimensional Cartesian Coordinate System can be obtained by a set of functions as follows
Similarly, given a Coordinate Location \((x, y, z)\) in 3 Dimensional Cartesian Coordinate System, the Coordinate
Location \((u, v, w)\) in a 3 Dimensional Curvilinear Coordinate System having Coordinate Axes \(U\) , \(V\) and \(W\) can be obtained by a set of functions as follows