[Numpy-discussion] "trapezoidal" grids

[Stéfan van der Walt]

On Fri, Feb 10, 2012 at 9:26 AM, Hugo Gagnon
<sourceforge.numpy@user.fastmail.fm> wrote:
> Hello,
>
> Say I have four corner points a = (X0, Y0), b = (X1, Y1), c = (X2, Y2)
> and d = (X3, Y3):
>
> a----------b
>  \        /
>  \      /
>   c----d
>
> Is there a function like meshgrid that would return me a grid of points
> linearly interpolating those four corner points?

It depends on what you mean by "linearly interpolating".  For example,
you can construct a regular grid and simply discard points outside the
trapesium, or assume that the trapesium is a "warped perspective" on a
regular grid.  For the latter case, you can construct a grid like
this:

http://mentat.za.net/refer/np_warped_grid.png

(code attached)

Stéfan
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