DAFmap: Direct forest patrols from threats

#' glad_by_date
#' 
#' Extracts the glad data for period of interest
#' 
#' @param from_date The start date for the period of interest
#' @param to_date The end date for the peiod of interest
#' @param sectors A SpatialPolygonsDataFrame describing the patrol sectors
#' @return  A raster containing all the forest loss events as ones and non-loss
#' as zeros for the period of interest
#' @export
#' @author Tom Swinfield
#' @details The functions period_to_dates or choose dates should be used to 
#' create the dates in a suitable format. 
#' 
#' Created 17-02-21

glad_by_date <- function(from_date, to_date, sectors) {
  period_days <- to_date - from_date
  to_data <- load_glad_by_date(to_date, sectors)
  
  to_data[is.na(to_data)] <- 0
  to_data[to_data > yday(to_date)] <- 0
  
  if (year(from_date) == year(to_date)) {
    to_data[to_data < yday(from_date)] <- 0
    to_data[to_data != 0] <- 1
  }
  else{
    from_data <- load_glad_by_date(from_date, sectors)
    from_data[from_data < yday(from_date)] <- 0
    to_data[from_data != 0] <- 1
  }
  return(to_data)
}

#' load_glad_by_date
#' 
#' Loads glad data for a specific year
#' 
#' @param date A date object which is used to describe the year of the data of interest
#' @param poly A SpatialPolygonsDataFrame describing the patrol sectors
#' @return A raster cropped to the area of interest
#' @export
#' @author Tom Swinfield
#' @details 
#' 
#' Created 17-02-21

load_glad_by_date <- function(date, poly) {
  regx <- paste("SEA_day_", year(date), ".*.tif$", sep = "")
  name <-
    list.files(path = "data/GLAD",
               pattern = regx,
               full.names = TRUE)
  data <- raster(name)
  data <- crop(data, extent(spTransform(poly, crs(data))))
  data <- projectRaster(data, crs = crs(poly))
}

#' period_to_dates
#' 
#' Converts a character string describing the period to a list containing
#' the dates of the start (from) and end (to) of the period.
#' 
#' @param analysis_period A character string describing the period
#' @return A list containing the dates the period started (from) and ended (to)
#' @export
#' @author Tom Swinfield
#' 
#' Created 17-02-21

period_to_dates <- function(analysis_period) {
  if (analysis_period == "Year to date")
    dates <- c(from_date = today() - period("1year"),
               to_date = today())
  if (analysis_period == "Quarter to date")
    dates <-
      c(from_date = today() - period("3months"),
        to_date = today())
  if (analysis_period == "Last year") {
    to_date <- floor_date(today(), "year") - days(1)
    from_date <- floor_date(to_date, "year")
    dates <- c(from_date = from_date, to_date = to_date)
  }
  if (analysis_period == "Last quarter") {
    to_date <- floor_date(today(), "quarter") - days(1)
    from_date <- floor_date(to_date, "quarter")
    dates <- c(from_date = from_date, to_date = to_date)
  }
  if (analysis_period == "Last month") {
    to_date <- floor_date(today(), "month") - days(1)
    from_date <- floor_date(to_date, "month")
    dates <- c(from_date = from_date, to_date = to_date)
  }
  if (analysis_period == "Last 60 days")
    dates <- c(from_date = today() - days(60), to_date = today())
  if (analysis_period == "Last 30 days")
    dates <- c(from_date = today() - days(30), to_date = today())
  
  id_names<-names(dates)
  names(dates)<-NULL
  dates<-as.list(dates)
  names(dates)<-id_names
  
  return(dates)
}

#' choose_dates
#' 
#' This is a wrapper for the function period_to_dates that 
#' creates a pop-up window to select the period of interest.
#' The options available are analogous to those in SMART.
#' 
#' @return A list containing the dates the period started (from) and ended (to)
#' @export
#' @author Tom Swinfield
#' @details 
#' 
#' Created 17-02-21

choose_dates<-function(){
  analysis_period<-select.list(c("Year to date", 
                               "Quarter to date",
                               "Last year",
                               "Last quarter",
                               "Last month",
                               "Last 60 days", 
                               "Last 30 days"
  ), title="Tolong buat seleksi periode", graphics=TRUE)
  period_to_dates(analysis_period)
}