R/bfmZoo.R

In loicdtx/bfastSpatial: Utilities to monitor for change on satellite image time-series

#' Runs bfastmonitor on a zoo object
#' 
#' @description This function is analog to the \link{bfastmonitor} function, but differs in terms of inputs. In \link{bfastmonitor} an object of class ts needs to be provided, usually pre-processed using \link{bfastts}; the present function accepts directly zoo time-series. The return also differs from \link{bfastmonitor}; instead of returning an object of class 'bfastmonitor'the present function returns a dataframe. The zoo object may contain several time-series, which results in a return dataframe containing several rows.
#' 
#' @param x A zoo object that may contain several time-series
#' @param mc.cores Numeric For parallel processing. Number of workers.
#' @param ... Arguments to be passed to \link{bfastmonitor}
#' 
#' @return A dataframe
#' 
#' @author Loic Dutrieux
#' 
#' @import bfast
#' 
#' @export
#' 


bfmZoo <- function(x, mc.cores = 1, ...) {
    
    bfm2df <- function(x) {
        if(class(x) == 'bfastmonitor') {
            data.frame(breakpoint = x$breakpoint,
                       magnitude = x$magnitude,
                       history = (x$history[2] - x$history[1]),
                       rsq = summary(x$model)$r.squared,
                       adj_rsq = summary(x$model)$adj.r.squared)
        } else if(class(x) == 'try-error') {
            data.frame(breakpoint = NA,
                       magnitude = NA,
                       history = NA,
                       rsq = NA,
                       adj_rsq = NA)
        }
        
    }
    
    bfastmonitorFun <- function(x, ...) {
        bfm <- try(bfastmonitor(x, ...))
        bfm2df(bfm)
    }
    
    ts <- bfastts(x, index(x), 'irregular')
    out <- mclapply(X = ts, FUN = bfastmonitorFun, mc.cores = mc.cores, ...)
    # Convert list to df
    do.call(rbind, out)
}