Re: [netcdfgroup] simple commandline query of data-variable statistics to stdout?

• To: netcdfgroup@xxxxxxxxxxxxxxxx,
• Subject: Re: [netcdfgroup] simple commandline query of data-variable statistics to stdout?
• From: Tom Roche <Tom_Roche@xxxxxxxxx>,
• Date: Sun, 09 Sep 2012 20:46:51 -0400

Kokron, Daniel S. Thu, 6 Sep 2012 20:15:31 -0500
>> Have a look at the 'grdinfo' utility which is part of GMT5.

>> http://www.soest.hawaii.edu/gmt5/

GMT looks interesting (and is available as a debian package) but
`grdinfo` seems to only work with 2d data (Am I missing something?)
E.g., for

$ ncdump -h ./GEIA_N2O_oceanic.nc
> netcdf GEIA_N2O_oceanic {
> dimensions:
>       lon = 360 ;
>       lat = 180 ;
>       time = UNLIMITED ; // (1 currently)
> variables:
...
>       double emi_n2o(time, lat, lon) ;
>              emi_n2o:units = "ton N2O-N/yr" ;
>              emi_n2o:missing_value = -999. ;
>              emi_n2o:long_name = "N2O emissions" ;
>              emi_n2o:_FillValue = -999.f ;
...
$ GMT grdinfo ./GEIA_N2O_oceanic.nc
> grdinfo: No 2-D variable in file [./GEIA_N2O_oceanic.nc]

Alas.

Charlie Zender Fri, 07 Sep 2012 10:16:19 -0700
> Your query matches a category of commands which I call filters[,
> e.g.] http://nco.sf.net/nco.html#filters [. Since] ncap2 [is]
> better for arbitrarily complex and longer filters

... I went with that, even though the bigot in me rails against the
requirement to write a file as a side effect. (Fortunately he was
appeased by use of tempfiles :-) `source`able bash follows my .sig.

your assistance is appreciated, Tom Roche <Tom_Roche@xxxxxxxxx>
---------------------code follows to end of post---------------------

# bash functions for NCO "filters", as suggested by Charlie Zender @
# 
http://www.unidata.ucar.edu/mailing_lists/archives/netcdfgroup/2012/msg00286.html
# http://nco.sourceforge.net/nco.html#filters
# All use `ncap2` and take input like $1=datavar name, $2=filename

# Prints maximum
function ncmax {
  TMPFILE="$(mktemp)"
  ncap2 -O -C -v -s "foo=${1}.max();print(foo)" ${2} ${TMPFILE} | cut -f 3- -d 
' '
}

function ncmin {
  TMPFILE="$(mktemp)"
  ncap2 -O -C -v -s "foo=${1}.min();print(foo)" ${2} ${TMPFILE} | cut -f 3- -d 
' '
}

# Prints mean
function ncmean {
  TMPFILE="$(mktemp)"
  ncap2 -O -C -v -s "foo=${1}.avg();print(foo)" ${2} ${TMPFILE} | cut -f 3- -d 
' '
}

# median not currently available?

# Prints RMS (root-mean-square, normalized by N)
function ncRMS {
  TMPFILE="$(mktemp)"
  ncap2 -O -C -v -s "foo=${1}.rms();print(foo)" ${2} ${TMPFILE} | cut -f 3- -d 
' '
}

# Prints range (of values in datavar)
function ncrange {
  TMPFILE="$(mktemp)"
  ncap2 -O -C -v -s \
    "foo=${1}.min();bar=${1}.max();print(foo,\"%f\");print(\" to 
\");print(bar,\"%f\")"\
     ${2} ${TMPFILE}
}

# Prints number of elements in datavar (including NA)
function ncsize {
  TMPFILE="$(mktemp)"
  ncap2 -O -C -v -s "foo=${1}.size();print(foo)" ${2} ${TMPFILE} | cut -f 3- -d 
' '
}

# Prints total
function nctotal {
  TMPFILE="$(mktemp)"
  ncap2 -O -C -v -s "foo=${1}.total();print(foo)" ${2} ${TMPFILE} | cut -f 3- 
-d ' '
}

• Follow-Ups:
  • Re: [netcdfgroup] simple commandline query of data-variable statistics to stdout?
    • From: Kokron, Daniel S. (GSFC-610.1)[Computer Sciences Corporation]

• References:
  • Re: [netcdfgroup] simple commandline query of data-variable statistics to stdout?
    • From: Kokron, Daniel S. (GSFC-610.1)[Computer Sciences Corporation]
  • [netcdfgroup] simple commandline query of data-variable statistics to stdout?
    • From: Tom Roche
  • Re: [netcdfgroup] simple commandline query of data-variable statistics to stdout?
    • From: Lynnes, Christopher S. (GSFC-6102)