R/aermod_stat_plt.R

In maxbre/myRfuns: My R collection of handy functions

#' Statistics of AERMOD PLT output file
#'
#' Calculate statistics for AERMOD PLT output file
#'
#' @param plt string for the aermod plt file
#' @param x_source numeric, x coordinate of the point source (or the centre or any point of the source)
#' @param y_source numeric, y coordinate of the point source (or the centre or any point of the source)
#'
#' @return a tibble with x and y coordinates, concentration values, distances from the source, compass degrees from the North corresponding to min and max statistics
#' @export
#' @examples \dontrun{
#' aermod_stat_plt('AERMOD.PLT', 739050, 5084550)
#' }

aermod_stat_plt<- function(plt,
                          x_source,
                          y_source){

  # read tbl data (call user function)
  tbl<-aermod_read_plt(plt)

  # index for min concentration
  i_min<-which.min(tbl$CONC)
  # value of min concentration
  c_min <- min(tbl$CONC)
  #c_min <- tbl$CONC[i_min]
  # x, y coordinates at min
  x_min <- tbl$X[i_min]
  y_min <- tbl$Y[i_min]

  # index for max concentration
  i_max<-which.max(tbl$CONC)
  # value of max concentration
  c_max <- max(tbl$CONC)
  #c_max <- tbl$CONC[i_max]
  # x, y coordinates at max
  x_max <- tbl$X[i_max]
  y_max <- tbl$Y[i_max]

  # linear distance of min concentration from the source
  d_min <-sqrt((x_source - x_min)^2+(y_source - y_min)^2)

  # linear distance of max concentration from the source
  d_max <- sqrt((x_source - x_max)^2+(y_source - y_max)^2)

  # calculate bearing angles
  # between the source point
  # and other relevant points (min, max, p98)

  # by recalling that
  # rad : pi = deg : 180
  # two functions to transform
  # from radians to degrees
  # from degrees to radians
  #rad2deg <- function(rad) {rad / pi * 180}
  #deg2rad <- function(deg) {deg / 180 * pi}

  # bearing angle for point at min distance
  #ba_min <- rad2deg(atan2((y_source - y_min), (x_source - x_min)))

  #bearing angle for point at max distance
  #ba_max <- rad2deg(atan2((y_source - y_max), (x_source - x_max)))

  # now is needed the transformation
  # from polar to compass degrees (from the North)

  # all that is dealt much more easily
  # with the use of complex number approach
  # SEE OTHER FUNCTIONS IN MY PKG!!!


  #(x_max - x_source)
  #(y_max - x_source)
  #deg<-car2deg((x_max - x_source), (y_max - x_source))

  deg_N_max<-car2deg_N((x_max - x_source), (y_max - x_source))
  deg_N_min<-car2deg_N((x_min - x_source), (y_min - x_source))

  #round(c(x_max, y_max, c_max, d_max, deg, deg_N),2)
  tib_max<-tibble::tibble(STAT="MAX", X=x_max, Y=y_max, CONC=c_max, DIST=d_max, DEG_N=deg_N_max)
  tib_min<-tibble::tibble(STAT="MIN", X=x_min, Y=y_min, CONC=c_min, DIST=d_min, DEG_N=deg_N_min)

  dplyr::bind_rows(tib_max, tib_min)

  }