On Sat, Dec 3, 2011 at 12:35 AM, Robin Kraft <[email protected]> wrote:
> I need to take an array - derived from raster GIS data - and upsample or
> scale it. That is, I need to repeat each value in each dimension so that,
> for example, a 2x2 array becomes a 4x4 array as follows:
>
> [[1, 2],
> [3, 4]]
>
> becomes
>
> [[1,1,2,2],
> [1,1,2,2],
> [3,3,4,4]
> [3,3,4,4]]
>
> It seems like some combination of np.resize or np.repeat and reshape +
> rollaxis would do the trick, but I'm at a loss.
>
> Many thanks!
>
> -Robin
>
Just a day or so ago, Josef Perktold showed one way of accomplishing this
using numpy.kron:
In [14]: a = arange(12).reshape(3,4)
In [15]: a
Out[15]:
array([[ 0, 1, 2, 3],
[ 4, 5, 6, 7],
[ 8, 9, 10, 11]])
In [16]: kron(a, ones((2,2)))
Out[16]:
array([[ 0., 0., 1., 1., 2., 2., 3., 3.],
[ 0., 0., 1., 1., 2., 2., 3., 3.],
[ 4., 4., 5., 5., 6., 6., 7., 7.],
[ 4., 4., 5., 5., 6., 6., 7., 7.],
[ 8., 8., 9., 9., 10., 10., 11., 11.],
[ 8., 8., 9., 9., 10., 10., 11., 11.]])
Warren
_______________________________________________
NumPy-Discussion mailing list
[email protected]
http://mail.scipy.org/mailman/listinfo/numpy-discussion
