tern_limits {ggtern}

Restrict Ternary Limits

Description

tern_limits (or its aliasses) appends new T, L and R ternary continuous scales, where the maximum scale value is specified, and, where the minimums for each are solved.

Usage

tern_limit(T = 1, L = 1, R = 1, ...)

limit_tern(...)

Arguments

T, L, R

numeric value (scalar) of the maximum T,L,R species limit for each scale respectively

...

other arguments to pass to ALL of scale_X_continuous (X = T, L, R)

Details

The contra value (ie minimum value) for the T, L and R species is solved using linear equations, therefore, if the solution is degenerate, or, the solution results in a zero range in either of the proposed scales, then a warning message will be reported and an empty list returned. Note that limits_tern(...), limit_tern(...) and tern_limit(...) are all aliasses for the main function, tern_limits(...) and can be used interchangeably.

Value

Either an empty list (when no solution can be found), or a list containing one of each of scale_X_continuous (X = T, L, R)

Author(s)

Nicholas Hamilton

See Also

scale_T_continuous, scale_L_continuous and scale_R_continuous

Examples

#Display a non-zoomed and zoomed plot side by side
data(Feldspar)
df.lims = data.frame(Ab = c(1,.25,.25), 
                     An = c(0,.75,.00), 
                     Or = c(0,.00,.75))
#Build the non-zoomed plot
A = ggtern(Feldspar,aes(Ab,An,Or)) +
 stat_density_tern(geom='polygon',aes(fill=..level..,alpha=..level..)) + 
 geom_point() + 
 geom_mask() + 
 geom_polygon(data=df.lims,color='red',alpha=0,size=0.5) +
 guides(color='none',fill='none',alpha='none') + 
 labs(title = "Non-Zoomed")

#Build the zoomed plot
B = A + 
  tern_limits(T=max(df.lims$An), L=max(df.lims$Ab), R=max(df.lims$Or)) +
  labs(title = "Zoomed")

#Arrange the above plots side by side for illustration
grid.arrange(A,B,ncol=2,top="Demonstration of Limiting Region")