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Added function for putting points in sequence for path plotting, see ?point.in.sequence
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‎DESCRIPTION

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'TRL-line.R'
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'multiplot.R'
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'ggsave.R'
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'point-in-sequence.R'

‎NAMESPACE

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export(weight_percent)
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export(atomic_percent)
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export(custom_percent)
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export(point.in.sequence)
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export(ggsave)

‎NEWS

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ggtern 1.0.3.2
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----------------------------------------------------------------
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* Added convenience functions, and global options for modifying the length of the ternary arrows easily.
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* Added function for putting points in sequence for path plotting, see ?point.in.sequence
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BUG FIXES
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* Fixed broken ggsave function, which was not using the local print function.

‎R/point-in-sequence.R

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#' Put Points in Sequence
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#'
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#' The \code{point.in.sequence} function takes numeric input vectors \code{x} and \code{y} or a
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#' \code{\link{data.frame}} object, and orders the values in such way that they are correctly sequenced by the angle subtended between each point,
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#' and, the centroid of the total set. If the data is provided in the format of a \code{data.frame}, then it must
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#' containing columns named \code{x} and \code{y}, else an error will be thrown.
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#'
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#' The arguments \code{x} and \code{y} represent cartesian coordinates. This is useful if a path is sought that
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#' passes through each point in the ordered set, however, no two lines in the total path cross over each other.
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#' Uses the \code{\link{atan2}} function to determine the angle (theta) between each point (x,y) and the centroid
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#' of the data, it then orders based on increasing values of theta.
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#'
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#' @param x vector of numeric \code{x} values
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#' @param y vector of numeric \code{y} values
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#' @param ... not used
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#' @param df data.frame containing colums \code{x} and \code{y}
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#' @param close logical value (default \code{FALSE}), as to whether the set should be closed by adding (duplicating)
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#' the first row (after ordering) to the end of the set.
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#' @return \code{data.frame} object containing the re-ordered input set.
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#' @examples
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#' \donttest{
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#' #Load plotting library
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#' library(ggplot2)
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#'
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#' #For reproducability
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#' set.seed(1)
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#'
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#' #Build data in an approximate loop
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#' theta <- seq(0,2*pi,by=pi/100)
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#' r <- 1 + (runif(length(theta))-0.5)/5
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#' df2 <- data.frame(x=r*cos(theta),y=r*sin(theta))
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#'
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#' #Randomise the order of the data
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#' df2 <- df2[sample(nrow(df2)),]
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#'
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#' #Function to plot data
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#' demo <- function(ret){
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#' ggplot(data=ret,aes(x,y)) +
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#' geom_path() +
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#' geom_point(fill="yellow",color="black",shape=21)
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#' }
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#'
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#' #Demonstrate how the data would plot WITHOUT sorting
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#' demo(df2)
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#'
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#' #Demonstrate how the data would plot WITH sorting
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#' demo(point.in.sequence(df=df2,close=TRUE))
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#' }
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#' @export
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point.in.sequence <- function(x,y,...,df=data.frame(x=x,y=y),close=FALSE){
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#If first argument is provided as data.frame, re-assign to df
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if(!missing(x))
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if(class(x) == "data.frame")
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df = x
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#Check df is dataframe
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if(class(df) != "data.frame")
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stop("df must be a data.frame",call.=F)
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#Check 2 or more unique rows exist.
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if(nrow(unique(df)) <= 1)
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stop("df must contain at least two unique rows",call.=FALSE)
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#Check correct columns exist
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sapply(c("x","y"),function(X){
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if(!X %in% colnames(df))
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stop(paste("df must contain column",X),call.=F)
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if(!is.numeric(df[,X]))
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stop(paste("df must contain column",X,"and must be numeric"),call.=F)
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})
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#Check close argument is logical
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close = ifthenelse(is.logical(close),close[1],FALSE)
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#Center point
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c.x = mean(df$x)
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c.y = mean(df$y)
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#Determine angle with center point
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df$theta <- apply(df[,c("x","y")],1,function(r) atan2(r[2] - c.y,r[1] - c.x)*180/pi)
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#Put in correct order and
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df <- df[with(df,base::order(theta)), ]
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#Make a closed loop if desired
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#by duplicating the first row on the bottom
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if(close)
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df <- rbind(df,df[1,])
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#Remove theta column
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df$theta=NULL
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#And return
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df
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}

‎man/point.in.sequence.Rd

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\name{point.in.sequence}
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\alias{point.in.sequence}
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\title{Put Points in Sequence}
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\usage{
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point.in.sequence(x, y, ...,
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df = data.frame(x = x, y = y), close = FALSE)
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}
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\arguments{
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\item{x}{vector of numeric \code{x} values}
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\item{y}{vector of numeric \code{y} values}
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\item{...}{not used}
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\item{df}{data.frame containing colums \code{x} and
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\code{y}}
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\item{close}{logical value (default \code{FALSE}), as to
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whether the set should be closed by adding (duplicating)
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the first row (after ordering) to the end of the set.}
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}
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\value{
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\code{data.frame} object containing the re-ordered input
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set.
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}
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\description{
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The \code{point.in.sequence} function takes numeric input
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vectors \code{x} and \code{y} or a
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\code{\link{data.frame}} object, and orders the values in
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such way that they are correctly sequenced by the angle
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subtended between each point, and, the centroid of the
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total set. If the data is provided in the format of a
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\code{data.frame}, then it must containing columns named
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\code{x} and \code{y}, else an error will be thrown.
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}
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\details{
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The arguments \code{x} and \code{y} represent cartesian
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coordinates. This is useful if a path is sought that
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passes through each point in the ordered set, however, no
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two lines in the total path cross over each other. Uses
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the \code{\link{atan2}} function to determine the angle
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(theta) between each point (x,y) and the centroid of the
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data, it then orders based on increasing values of theta.
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}
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\examples{
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\donttest{
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#Load plotting library
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library(ggplot2)
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#For reproducability
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set.seed(1)
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#Build data in an approximate loop
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theta <- seq(0,2*pi,by=pi/100)
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r <- 1 + (runif(length(theta))-0.5)/5
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df2 <- data.frame(x=r*cos(theta),y=r*sin(theta))
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#Randomise the order of the data
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df2 <- df2[sample(nrow(df2)),]
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#Function to plot data
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demo <- function(ret){
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ggplot(data=ret,aes(x,y)) +
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geom_path() +
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geom_point(fill="yellow",color="black",shape=21)
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}
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#Demonstrate how the data would plot WITHOUT sorting
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demo(df2)
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#Demonstrate how the data would plot WITH sorting
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demo(point.in.sequence(df=df2,close=TRUE))
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}
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}
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