[Numpy-discussion] creating zonal statistics from two arrays
Matt Gregory
matt.gregory at oregonstate.edu
Mon Dec 20 15:44:17 EST 2010
On 12/8/2010 9:48 AM, josef.pktd at gmail.com wrote:
> Just a thought since I'm not doing spatial statistics.
>
> If you can create (integer) labels that assigns each point to a zone,
> then you can treat it essentially as a 1d grouped data, and you could
> use np.bincount to calculate some statistics, or alternatively
> scipy.ndimage.measurements for some additional statistics.
>
> This would avoid any python loop, but require a full label array.
Josef,
The measurements module did the trick; thanks for the pointer. I just
stumbled across a very similar thread on the scipy listserv that you
answered basically the same question with some nice code (sorry for the
redundancy):
http://mail.scipy.org/pipermail/scipy-user/2009-February/019850.html
BTW, the OP on that thread (Jose Gomez-Dans) has a script out there for
doing just this type of operation that I was after:
http://sites.google.com/site/spatialpython/zonal-statistics
thanks, matt
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