On Sat, Dec 3, 2011 at 12:35 AM, Robin Kraft <rkraft4@gmail.com> 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