This applies a single pole low pass digital filter to all data. This time constant is compensated for variable intervals between values. Note that some types of averaging require inputs beyond the values being averaged. For example, to average raw absorptions, transmittance and path length are required because the average is performed with a difference measurement.
Usage
da.smooth.1plp [switches…] [[station] variables times [archive]|[file]]
Switches
- --gap=INTERVAL
-
If two values are seperated by this much time then the smoother is reset. That is, data separated by this much will be smoothed as independent runs of data.
Default: Infinite
Undefined intervals are accepted. The interval must be greater than or equal to zero length.
- --ignore-undefined[=BOOLEAN]
-
If this option is set undefined values are ignored instead of forcing a smoother reset.
Default: Disabled, undefined values cause a reset
- --tc=INTERVAL
-
This is the time constant of the filter. A time constant for a digital filter is the time required for a step change in values to reach 63.2% of the final value.
Default: Three minutes
The interval must be greater than zero in length.
Arguments
If no bare word input specification is supplied then data are read from standard input.
- station
-
This argument is used to specify the station used to look up variables that do not include a station as part of an archive read specification. The station is the three letter GAW station code of the location, such as
BND
. The argument accepts multiple stations specified as regular expressions and separated by:
or;
or,
. For exampleBND,MLO
and(BND|MLO)
are two ways of selecting both the BND and MLO stations.The special value
allstations
may also be specified to select all stations. - variables
-
This argument may be split into multiple actual program arguments. Each part consists of one or more variable specifications separated by
,
(commas). The station and archive used if none are explicitly given are defined in the other arguments or inferred from system defaults. For example simplyBsB_S11
selects the blue scattering from the S11 instrument and returns all cut sizes and metadata. If instead::BsB_S11:pm10
is used then only PM10 scattering is returned. That is, the selection specifies "any" station and archive (the defaults are set in the other arguments) then requires that it has the "PM10" flavor. A specification such asbnd:BsB_S11,thd:BsB_S11
allows for data selection from multiple stations.This may also be used to select a "record" type alias such as "S11a". In this mode all the variables defined in the alias are returned.
Finally the special value
everything
can be used to select all available data for the given station(s) and archive(s). - times
-
This argument may be split into multiple actual program arguments. This full list of time arguments defines a time bounds list that sets the range of data queried. The final resulting data are clipped to the given time bounds but any values that intersect them are returned.
- archive
-
This argument is used to specify the archive used to look up variables that do not include an archive as part of an archive read specification. The archive is the internal name, such as
raw
orclean_meta
. The argument accepts multiple archives specified as regular expressions and separated by:
or;
or,
. For exampleraw(_meta)?
selects both theraw
andraw_meta
archives.The special value
allarchives
may also be used to select all available archives. - file
-
This argument is used to specify the the file to read data from. If it is present and exists then data is read from the given file name instead of from standard input. Alternatively
-
(a single dash) may be used to explicitly specify standard input.
Examples
- Default
-
This smooths all available data with a single pole low pass digital filter with a time constant of three minutes. Gaps of any size are smoothed over (taken as continuous sequences of data) but undefined values cause the smoother to reset.
da.smooth.1plp bnd S11a 2015-05-01 2015-05-03
Or:
da.smooth.1plp input_file.c3d
Or:
da.get bnd S11a 2015-05-01 2015-05-03 | da.smooth.1plp
- Alternate time constant
-
This smooths data with a digital filter with a time constant of one hour.
da.smooth.1plp --tc=1h bnd S11a 2015-05-01 2015-05-03