R. And it has netcdf functions also.
-Roy M.
On May 11, 2008, at 8:07 PM, Timothy Hume wrote:
I think the reason why functions for calculating quartiles (or more
generally, percentiles) are not in many software packages is
because they can be computationally expensive to compute.
The only way I know how to generate percentiles is to first sort
the data into numeric order, and then select the appropriate value
from the list. Sorting is expensive, especially when there are a
lot of data. Is there a better/faster way of computing percentiles?
Tim Hume
Centre for Australian Weather and Climate Research
Melbourne
Australia
-----Original Message-----
From: Gerry Creager [mailto:gerry.creager@xxxxxxxx]
Sent: Monday, 12 May 2008 12:41
To: Timothy Hume
Cc: Dennis Shea
Subject: Re: [netcdfgroup] Calculating medians, quartiles etc of a
variable in a NetCDF file.
I'd consider looking at the NCAR command language and seeing if
quartile
calculation is native therein. I'd be surprised if it's not, or
easily
computable, but I did not find it initially.
Check http://www.ncl.ucar.edu/ and consider joining the mailing list
long enough to find out.
Timothy Hume wrote:
Hi,
I have an application where I would like to calculate quartiles of
a variable in a NetCDF file (I am computing the trimean: TM = 0.25*
(Q1 + 2Q2 + Q3) )
The NetCDF operators are excellent for computing arithmetic means,
but don't include the capability to compute quartiles. Before I
start writing my own code to compute quartiles, does anyone know
of some software which already does this? Basically, I am looking
for the equivalent of ncwa with a quartile operation.
Thanks,
Tim Hume
Centre for Australian Weather and Climate Research
Melbourne
Australia
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Texas Mesonet -- AATLT, Texas A&M University
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