[SciPy-user] step in arrays

Agustin Lobo scipy-user@scipy.net
Mon, 3 Feb 2003 13:02:14 +0100 (MET)


Hi! 
I would need a little help on this:

I want to read a set of images
(raw bin data, unsigned int*8) and
display them using xply.imagesc just
to mae sure there have been no errors at downloding
them.

For each file, I'm doing the following:

f =open("NDVI_GIMMS_8KM.8107","r")
a=f.read()
b = array(a,typecode=UnsignedInt8)
b.shape = (2168,5004)
xplt.imagesc(b)

The problem is that, as the array "b" is very large,
the display takes too long. Therefore, I'm trying
to subsample b. I've tried with take(), but no luck.
The question is, how could I select every i.e. 10th row
and col from matrix b?

Also, any other comment on improving what I want to do
is welcome! (perhaps I can subsample at reading).

Thanks

Agus


Dr. Agustin Lobo
Instituto de Ciencias de la Tierra (CSIC)
Lluis Sole Sabaris s/n
08028 Barcelona SPAIN
tel 34 93409 5410
fax 34 93411 0012
alobo@ija.csic.es