image.asc {adehabitat} | R Documentation

## Displays a Color Image of an Object of Class 'asc'

### Description

These functions display a raster matrix of class `asc`.

### Usage

    image.asc(x, clfac = NULL, col = gray((240:1)/256), ...)
    contour.asc(x, ...)
    persp.asc(x, ...)
    plot.asc(x, ...)

### Arguments

`x` | an object of class `asc`
`clfac` | for maps of type `"factor"`, a character vector giving the names of colors for each level of the factor (see `help(colasc)`)
`col` | for maps of type `"numeric"`, the colors to be used (see `help(par)`)
`...` | additional arguments to be passed to the generic function `image`, `persp`, `contour`, and `filled.contour` (but see below)

### Note

The function `plot.asc` uses the function `filled.contour`. The output produced by `filled.contour` is actually a combination of two plots; one is the filled contour and one is the legend. Two separate coordinate systems are set up for these two plots, but they are only used internally - once the function has returned these coordinate systems are lost. If you want to annotate the main contour plot, for example to add points, you can specify graphics commands in the `plot.axes` argument of the function `filled.contour` (this argument is to be passed to the function `plot.asc`). An example is given below.

### Author(s)

Clément Calenge calenge@biomserv.univ-lyon1.fr

### See Also

`image`, `contour`, `persp`, `filled.contour`, `import.asc`

### Examples

    data(puechabon)

    # Case of a continuous variable: the elevation
    my.map <- getkasc(puechabon$kasc, "Elevation")
    image(my.map, main = "Elevation in Puechabon")
    contour(my.map, add = TRUE)

    # use of the function plot.asc: adding points on the map
    plot(my.map, plot.axes = {points(puechabon$locs[,c("X","Y")])},
         main = "Elevation")

    # Case of a factor: the aspect
    asp <- getkasc(puechabon$kasc, "Aspect")
    cl <- colasc(asp, NorthEast = "blue", SouthEast = "red",
                 SouthWest = "orange", NorthWest = "green")

    ## graphical display
    image(asp, clfac = cl, main = "Aspect", xlab = "Lambert X",
          ylab = "Lambert Y")
    legend(706500, 3162000, legend = levels(asp), fill = cl,
           cex = 0.7)

    opar<-par(mar = c(0,0,3,0), bg = "slategray")
    persp(my.map, scale = FALSE, box = FALSE, border = NA, shade = 0.75,
          col = "darkolivegreen3", expand = 2, theta = -60, phi = 30,
          main = "The topography of Puechabon")
    par(opar)

[Package adehabitat version 1.4 Index]