image.SpatialGridDataFrame | R Documentation |
Create image for gridded data in SpatialGridDataFrame or SpatialPixelsDataFrame objects.
## S3 method for class 'SpatialGridDataFrame'
image(x, attr = 1, xcol = 1, ycol = 2,
col = heat.colors(12), red=NULL, green=NULL, blue=NULL,
axes = FALSE, xlim = NULL,
ylim = NULL, add = FALSE, ..., asp = NA, setParUsrBB=FALSE,
interpolate = FALSE, angle = 0,
useRasterImage = !(.Platform$GUI[1] == "Rgui" &&
getIdentification() == "R Console") && missing(breaks), breaks,
zlim = range(as.numeric(x[[attr]])[is.finite(x[[attr]])]))
## S3 method for class 'SpatialPixelsDataFrame'
image(x, ...)
## S3 method for class 'SpatialPixels'
image(x, ...)
## S3 method for class 'SpatialGridDataFrame'
contour(x, attr = 1, xcol = 1, ycol = 2,
col = 1, add = FALSE, xlim = NULL, ylim = NULL, axes = FALSE,
..., setParUsrBB = FALSE)
## S3 method for class 'SpatialPixelsDataFrame'
contour(x, ...)
as.image.SpatialGridDataFrame(x, xcol = 1, ycol = 2, attr = 1)
image2Grid(im, p4 = as.character(NA), digits=10)
x |
object of class SpatialGridDataFrame |
attr |
column of attribute variable; this may be
the column name in the data.frame of |
xcol |
column number of x-coordinate, in the coordinate matrix |
ycol |
column number of y-coordinate, in the coordinate matrix |
col |
a vector of colors |
red , green , blue |
columns names or numbers given instead of the |
axes |
logical; should coordinate axes be drawn? |
xlim |
x-axis limits |
ylim |
y-axis limits |
zlim |
data limits for plotting the (raster, attribute) values |
add |
logical; if FALSE, the image is added to the plot layout setup
by |
... |
arguments passed to image, see examples |
asp |
aspect ratio to be used for plot |
setParUsrBB |
default FALSE, see |
useRasterImage |
if TRUE, use |
breaks |
class breaks for coloured values |
interpolate |
default FALSE, a logical vector (or scalar) indicating whether to apply linear interpolation to the image when drawing, see |
angle |
default 0, angle of rotation (in degrees, anti-clockwise from positive x-axis, about the bottom-left corner), see |
im |
list with components named x, y, and z, as used for |
p4 |
CRS object, proj4 string |
digits |
default 10, number of significant digits to use for checking equal row/column spacing |
as.image.SpatialGridDataFrame
returns the list with
elements x
and y
, containing the coordinates of the cell
centres of a matrix z
, containing the attribute values in matrix
form as needed by image.
Providing xcol
and ycol
attributes seems obsolete,
and it is for 2D data, but it may provide opportunities for plotting
certain slices in 3D data. I haven't given this much thought yet.
filled.contour seems to misinterpret the coordinate values, if we take the image.default manual page as the reference.
Edzer Pebesma
image.default, SpatialGridDataFrame-class,
levelplot in package lattice
. Function
image.plot
in package fields
can be used to make a legend for an
image, see an example in https://stat.ethz.ch/pipermail/r-sig-geo/2007-June/002143.html
data(meuse.grid)
coordinates(meuse.grid) = c("x", "y") # promote to SpatialPointsDataFrame
gridded(meuse.grid) = TRUE # promote to SpatialGridDataFrame
data(meuse)
coordinates(meuse) = c("x", "y")
image(meuse.grid["dist"], main = "Distance to river Meuse")
points(coordinates(meuse), pch = "+")
image(meuse.grid["dist"], main = "Distance to river Meuse",
useRasterImage=TRUE)
points(coordinates(meuse), pch = "+")
# color scale:
layout(cbind(1,2), c(4,1),1)
image(meuse.grid["dist"])
imageScale(meuse.grid$dist, axis.pos=4, add.axis=FALSE)
axis(4,at=c(0,.2,.4,.8), las=2)
data(Rlogo)
d = dim(Rlogo)
cellsize = abs(c(gt[2],gt[6]))
cells.dim = c(d[1], d[2]) # c(d[2],d[1])
cellcentre.offset = c(x = gt[1] + 0.5 * cellsize[1], y = gt[4] - (d[2] - 0.5) * abs(cellsize[2]))
grid = GridTopology(cellcentre.offset, cellsize, cells.dim)
df = as.vector(Rlogo[,,1])
for (band in 2:d[3]) df = cbind(df, as.vector(Rlogo[,,band]))
df = as.data.frame(df)
names(df) = paste("band", 1:d[3], sep="")
Rlogo <- SpatialGridDataFrame(grid = grid, data = df)
summary(Rlogo)
image(Rlogo, red="band1", green="band2", blue="band3")
image(Rlogo, red="band1", green="band2", blue="band3",
useRasterImage=FALSE)
is.na(Rlogo$band1) <- Rlogo$band1 == 255
is.na(Rlogo$band2) <- Rlogo$band2 == 255
is.na(Rlogo$band3) <- Rlogo$band3 == 255
Rlogo$i7 <- 7
image(Rlogo, "i7")
image(Rlogo, red="band1", green="band2", blue="band3", add=TRUE)
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