R/sph2cart.R

In HiveR: 2D and 3D Hive Plots for R

#' Convert Spherical to Cartesian Coordinates
#'
#' This function converts spherical to Cartesian coordinates.
#'
#'
#' @param df A data frame with columns named r, theta and phi with the radius
#' and angles (in spherical coordinates) to be converted to Cartesian
#' coordinates.
#'
#' @return A data frame with named columns containing the converted
#' coordinates.
#'
#' @note Cobbled together from similar functions in other packages.
#'
#' @author Bryan A. Hanson, DePauw University. \email{hanson@@depauw.edu}
#'
#' @keywords utilities
#'
#' @export sph2cart
#'
sph2cart <- function(df) {

  # Bryan Hanson
  # DePauw Univ, Feb 2011

  theta <- df$theta * 2 * pi / 360 # input angles in degrees
  phi <- df$phi * 2 * pi / 360
  x <- df$r * cos(theta) * sin(phi)
  y <- df$r * sin(theta) * sin(phi)
  z <- df$r * cos(phi)
  ans <- data.frame(x, y, z)
} # answer in degrees