8.8 Return a Wire Frame Specification: xyz_wf

Calling Sequence

xyz_wf (z, [y, x] [,scale = 1.0])

Description

Returns a 3-by-ni-by-nj array whose 0^th entry is x, 1^th entry is y, and 2^th entry is z. z is ni-by-nj. x and y, if present, must be the same shape. If not present, integer ranges will be used to create an equally spaced coordinate grid in x and y. The function which scales the ``topography'' of z(x,y) is potentially useful apart from plwf.

For example, the xyz array used by plwf can be converted from a quadrilateral mesh plotted using plf to a polygon list plotted using plfp like this:

xyz= xyz_wf(z,y,x,scale=scale)

ni= z.shape[1]

nj= z.shape[2]

list = ravel (add.outer (

ravel(add.outer (adders,zeros(nj-1, Int))) +

arange((ni-1)*(nj-1), typecode = Int),

array ( [[0, 1], [nj + 1, nj]])))

xyz=array([take(ravel(xyz[0]),list),

take(ravel(xyz[1]),list),

take(ravel(xyz[2]),list)])

nxyz= ones((ni-1)*(nj-1)) * 4;

The resulting array xyz is 3-by-(4*(nj-1)*(ni-1)). xyz[0:3,4*i:4*(i+1)] are the clockwise coordinates of the vertices of cell number i.