lim0: axis limits with one end at zero

In berryFunctions: Function Collection Related to Plotting and Hydrology

axis limits with one end at zero

Description

Calculates the range needed for ylim or xlim in plot, so that axis starts at zero and is extended by 4% at the other end

Usage

lim0(x, f = 1/27, curtail = TRUE)

Arguments

x	Numeric. Vector with values
f	Numeric. Extension factor. DEFAULT: 0.04 as in extendrange used eg. by curve
curtail	Logical. Should the range returned be trimmed by 4%? That way, plotting doesn't need the default par xaxs or yaxs changed. DEFAULT: TRUE

Value

Vector with two values: 0 and by 4

Author(s)

Berry Boessenkool, [e-mail], 6.6.2013

References

methods(plot), plot.default. Actually, I found extendrange via plot.function in curve

See Also

The extendrange() utility in package grDevices

Examples

# basic idea:
val <- c(3.2, 1.8, 4.5, 2.8, 0.1, 2.9) # just some numbers
plot(val, ylim=lim0(val) ) # you don't even have to set yaxs="i" ;-)

# "normal" plot:
plot(val)
par("usr")  # -0.076  4.676

# if y-axis is not allowed to go below 0, and we're too lazy to set yaxs="i":
plot(val, ylim=lim0(val) )
round( par("usr")  , digits=5) # 0.00000 4.66296

# with 0.04 extension as claimed by help page (1/27 in source code = 0.037):
plot(val, ylim=lim0(val, f=0.04) )
round( par("usr")  , digits=5) # zero is not included on axis anymore

b <- -val
plot(b)
plot(b, ylim=lim0(b) ) # works with only negative values as well

# can handle only-NA input:
lim0(c(7,NA,NA,NA)[-1])
lim0(c(NA,NA,NA))

berryFunctions documentation built on May 29, 2024, 4:01 a.m.