NCL Home > Documentation > Functions > Graphics routines


Retrieves the parallelogram coordinates of a point in the reference parallelogram, given a point in the projection plane (for use with selected TDPACK routines.)

Available in version 4.3.1 and later.


	function tdprpi (
		xyi2d [2] : float   

	return_val [2] :  float



A float array of 2 elements specifying the coordinates of a point in the projection plane.

Return value

A float array of two elements containing the parallelogram coordinates of that point in the reference parallelogram that projects into (xyi2d(0), xyi2d(1)).


This function is part of the low-level TDPACK package, which is a group of Fortran and C callable routines for projecting objects from a 3-dimensional coordinate system having U, V, and W axes to a 2-dimensional projection plane having X and Y axes and/or for drawing the projections of those objects. This can be referred to somewhat loosely as "drawing objects in three dimensions".

Please see the documentation on TDPRPI for a full description of this function.

See Also

Initialization routines: tdinit, tdpara, tdclrs

Parameter access routines: tdgetp, tdgtrs, tdsetp, tdstrs

Point transforming routines: tdprpt, tdprpa

Line drawing routines: tdline, tdlndp, tdlnpa, tdlpdp, tdcurv, tdcudp

Grid drawing routines: tdgrds, tdgrid

Label drawing routines: tdlbls, tdlbla, tdlblp, tdplch

Surface drawing routines: tddtri, tdstri, tditri, tdmtri, tdttri, tdctri, tdotri, tdsort

Simplified interface routines: tdez2d, tdez3d


No examples are currently available for this function. Please see the documentation on TDPRPI for more information about this function.