# Draw Symbols (User Defined) on a Plot This function draws symbols on a plot. It is similar to the builtin `symbols` function with the difference that it plots symbols defined by the user rather than a prespecified set of symbols. ```r my.symbols(x, y=NULL, symb, inches=1, xsize, ysize, add=TRUE, vadj=0.5, hadj=0.5, symb.plots=FALSE, xlab=deparse(substitute(x)), ylab=deparse(substitute(y)), main=NULL, xlim=NULL, ylim=NULL, linesfun=lines, ..., MoreArgs) ``` ## Arguments - `x, y`: The `x` and `y` coordinates for the position of the symbols to be plotted. These can be specified in any way which is accepted by `xy.coords`. - `symb`: Either a matrix, list, or function defining the symbol to be plotted. If it is a matrix or list it needs to be formatted that it can be passed directly to the `lines` function. It then defines the shape of the symbol on on a range/domain of -1 to 1. If this is a function it can either return a matrix or list as above (points on the range/domain of -1 to 1), or it can do the plotting itself. - `inches`: The size of the square containing the symbol in inches (note: unlike `symbols` this cannot be `FALSE`). This is ignored if `xsize` or `ysize` is specified. - `xsize`: The width of the bounding box(s) of the symbols in the same units as the `x` variable. Computed from `ysize` or `inches` if not specified. Can be a single value or a vector. - `ysize`: The height of the bounding box(s) of the symbols in the same units as the `y` variable. Computed from `xsize` or `inches` if not specified. Can be a single value or a vector. - `add`: if 'add' is 'TRUE' then the symbols are added to the existing plot, otherwise a new plot is created. - `vadj,hadj`: Numbers between 0 and 1 indicating how 'x' and 'y' specify the location of the symbol. The defaults center the symbol at x,y; 0 means put the bottom/left at x,y; and 1 means put the top/right of the symbol at x,y. - `symb.plots`: If `symb` is a function that does its own plotting, set this to TRUE, otherwise it should be FALSE. - `xlab, ylab, main, xlim, ylim`: If 'add' is 'FALSE' these are passed to the `plot` function when setting up the plot. - `linesfun`: The function to draw the lines if the function does not do its own drawing. The default is `lines` but could be replaced with `polygon` to draw filled polygons - `...`: Additional arguments will be replicated to the same length as `x` then passed to `symb` (if `symb` is a function) and/or the `lines` function (one value per symbol drawn). - `MoreArgs`: A list with any additional arguments to be passed to the `symb` function (as is, without being replicated/split). ## Details The `symb` argument can be a 2 column matrix or a list with components 'x' and 'y' that defines points on the interval [-1,1] that will be connected with lines to draw the symbol. If you want a closed polygon then be sure to replicate the 1st point as the last point. If any point contains an NA then the line will not be drawn to or from that point. This can be used to create a symbol with disjoint parts that should not be connected. If `symb` is a function then it should include a '...' argument along with any arguments to define the symbol. Any unmatched arguments that end up in the '...' argument will be replicated to the same length as 'x' (using the `rep` function) then the values will be passed one at a time to the `symb` function. If `MoreArgs` is specified, the elements of it will also be passed to `symb` without modification. The `symb` function can either return a matrix or list with the points that will then be passed to the `lines` function (see above). Or the function can call the plotting functions itself (set `symb.plots` to TRUE). High level plotting can be done (`plot`, `hist`, and other functions), or low level plotting functions (`lines`, `points`, etc) can be used; in this case they should add things to a plot with 'x' and 'y' limits of -1 to 1. The size of the symbols can be specified by using `inches` in which case the symbol will be set inside of squares whose sizes are `inches` size based on the plotting device. The size can also be set using `xsize` and/or `ysize` which use the same units as the `x` and/or `y` variables. If only one is specified then the box will be square. If both are specified and they do not match the aspect ratio of the plot then the bounding box will not be square and the symbol will be distorted. ## Returns This function is run for its side effect of plotting, it returns an invisible NULL. ## Author(s) Greg Snow 538280@gmail.com ## Note Since the '...' argument is passed to both `lines` and `symb`, the `symb` function should have a '...' argument so that it will ignore any additional arguments. Arguments such as 'type' can be passed through the '...' argument if you want the symbol made of something other than lines. Plotting coordinates and sizes are based on the size of the device at the time the function is called. If you resize the device after plotting, all bets are off. Currently missing values in `x` or `y` are not handled well. It is best if remove all missing values first. ## See Also `symbols`, `subplot`, `mapply`, `ms.polygram`, `lines` ## Examples ```r # symb is matrix my.symbols( 1:10, runif(10), ms.male, add=FALSE, xlab='x', ylab='y', inches=0.3, col=c('blue','green'), xlim=c(0,11), ylim=c(-0.1,1.1)) my.symbols( (1:10)+0.5, runif(10), ms.female, add=TRUE, inches=0.3, col=c('red','green') ) # symb is function returning matrix plot(1:10, 1:10) my.symbols( 1:10, 1:10, ms.polygram, n=1:10, inches=0.3 ) # symb is plotting function # create a variation on monthplot fit <- lm( log(co2) ~ time(co2) ) fit.r <- resid(fit) x <- 1:12 y <- tapply(fit.r, cycle(co2), mean) tmp.r <- split( fit.r, cycle(co2) ) tmp.r <- lapply( tmp.r, function(x) x-mean(x) ) yl <- do.call('range',tmp.r) tmpfun <- function(w,data,ylim,...){ tmp <- data[[w]] plot(seq(along=tmp),tmp, type='l', xlab='',ylab='', axes=FALSE, ylim=ylim) lines(par('usr')[1:2], c(0,0), col='grey') } my.symbols(x,y, symb=tmpfun, inches=0.4, add=FALSE, symb.plots=TRUE, xlab='Month',ylab='Adjusted CO2', xlim=c(0.5,12.5), ylim=c(-0.012,0.012), w=1:12, MoreArgs=list(data=tmp.r,ylim=yl) ) # using xsize and ysize plot( 1:10, (1:10)*100, type='n', xlab='', ylab='' ) my.symbols( 5, 500, ms.polygon, n=250, inches=1.5 ) my.symbols( 5, 500, ms.polygon, n=250, xsize=2, col='blue' ) my.symbols( 5, 500, ms.polygon, n=250, ysize=200, col='green' ) my.symbols( 5, 500, ms.polygon, n=250, xsize=2, ysize=200, col='red' ) abline( v=c(4,6), col='grey' ) abline( h=c(400, 600), col='grey' ) # hand crafted hexagonal grid x1 <- seq(0, by=2*sqrt(3), length.out=10) y1 <- seq(0, by=3, length.out=10) mypoints <- expand.grid(x=x1, y=y1) mypoints[,1] <- mypoints[,1] + rep( c(0,sqrt(3)), each=10, length.out=100 ) plot(mypoints, asp=1, xlim=c(-2,35)) my.symbols(mypoints, symb=ms.filled.polygon, n=6, inches=par('pin')[1]/(diff(par('usr')[1:2]))*4, bg=paste('gray',1:100,sep=''), fg='green' ) ```

mysymbols function