decimate: Smooth and Decimate, or Subsample, an Oce Object

Description

Later on, other methods will be added, and ctdDecimate() will be retired in favour of this, a more general, function. The filtering is done with the filter() function of the stats package.

Usage

decimate(x, by = 10, to, filter, debug = getOption("oceDebug"))

Arguments

an '>oce object.

an indication of the subsampling. If this is a single number, then it indicates the spacing between elements of x that are selected. If it is two numbers (a condition only applicable if x is an echosounder object, at present), then the first number indicates the time spacing and the second indicates the depth spacing.

Indices at which to subsample. If given, this over-rides by.

filter

optional list of numbers representing a digital filter to be applied to each variable in the data slot of x, before decimation is done. If not supplied, then the decimation is done strictly by sub-sampling.

debug

a flag that turns on debugging. Set to 1 to get a moderate amount of debugging information, or to 2 to get more.

Value

An '>oce object that has been subsampled appropriately.

Bugs

Only a preliminary version of this function is provided in the present package. It only works for objects of class echosounder, for which the decimation is done after applying a running median filter and then a boxcar filter, each of length equal to the corresponding component of by.

Examples

Run this code

# NOT RUN {
library(oce)
data(adp)
plot(adp)
adpDec <- decimate(adp,by=2,filter=c(1/4, 1/2, 1/4))
plot(adpDec)
# }