R/predefinedMeasurementMethod.R

In miquelcaceres/VegX: Vegetation data in Veg-X

#' Predefined measurement methods
#'
#' Creates a measurement method for Veg-X documents from a set of predefined options
#'
#' @param name A string with the desired measurement method or a subject (in this case, the default method is returned). 
#' The list of available predefined methods and subjects is found in \code{\link{quantitative_methods}}.
#'
#'
#' @return an object of class \code{\linkS4class{VegXMethodDefinition}}
#'
#' @family define measurement functions
#'
#' @examples
#' # Create a method for plant percent cover
#' predefinedMeasurementMethod("Plant cover/%")
#'
predefinedMeasurementMethod<-function(name) {
  quantitative_methods = get("quantitative_methods")
  m = NULL
  l = -1
  if(name %in% quantitative_methods$name) {
    l = which(quantitative_methods$name==name)
  } else if(name %in% quantitative_methods$subject) {
    s = which(quantitative_methods$subject==name)
    l = s[which(quantitative_methods$default[s]=="Yes")]
  } 
  if(l!=-1) {
    m = defineQuantitativeScaleMethod(name = quantitative_methods$name[l],
                                      description = quantitative_methods$description[l],
                                      subject = quantitative_methods$subject[l],
                                      unit = quantitative_methods$unit[l],
                                      lowerLimit = as.numeric(quantitative_methods$lowerLimit[l]),
                                      upperLimit = as.numeric(quantitative_methods$upperLimit[l]))
    return(m)
  } else {
    stop(paste0(name, " is not among the predefined methods."))
  }
}