Find an R package R language docs Run R in your browser

grid: Add Grid to a Plot

grid	R Documentation

Add Grid to a Plot

Description

grid adds an nx by ny rectangular grid to an existing plot.

Usage

grid(nx = NULL, ny = nx, col = "lightgray", lty = "dotted",
     lwd = par("lwd"), equilogs = TRUE)

Arguments

`nx, ny`	number of cells of the grid in x and y direction. When `NULL`, as per default, the grid aligns with the tick marks on the corresponding default axis (i.e., tickmarks as computed by `axTicks`). When `NA`, no grid lines are drawn in the corresponding direction.
`col`	character or (integer) numeric; color of the grid lines.
`lty`	character or (integer) numeric; line type of the grid lines.
`lwd`	non-negative numeric giving line width of the grid lines.
`equilogs`	logical, only used when log coordinates and alignment with the axis tick marks are active. Setting `equilogs = FALSE` in that case gives non equidistant tick aligned grid lines.

Note

If more fine tuning is required, use abline(h = ., v = .) directly.

References

Murrell, P. (2005) R Graphics. Chapman & Hall/CRC Press.

Examples

plot(1:3)
grid(NA, 5, lwd = 2) # grid only in y-direction

## maybe change the desired number of tick marks:  par(lab = c(mx, my, 7))
op <- par(mfcol = 1:2)
with(iris,
     {
     plot(Sepal.Length, Sepal.Width, col = as.integer(Species),
          xlim = c(4, 8), ylim = c(2, 4.5), panel.first = grid(),
          main = "with(iris,  plot(...., panel.first = grid(), ..) )")
     plot(Sepal.Length, Sepal.Width, col = as.integer(Species),
          panel.first = grid(3, lty = 1, lwd = 2),
          main = "... panel.first = grid(3, lty = 1, lwd = 2), ..")
     }
    )
par(op)