Objects can be created by calls of the form
as(x,
"SpatialPixelsDataFrame")
, where
x
is of class
SpatialPointsDataFrame-class
, or by importing through rgdal.
Ordered full grids are stored instead or unordered non-NA cells;
Slots
bbox
:
Object of class
"matrix"
; bounding box
proj4string
:
Object of class
"CRS"
; projection
coords
:
see
SpatialPoints
; points slot
coords.nrs
see
SpatialPointsDataFrame
grid
:
see
GridTopology-class
; grid parameters
grid.index
:
integer; index of points in the list to points
in the full (ordered) grid. x cycles fastest; all coordinates increase
from low to hight except y, which decreases from high to low
data
:
Object of class data.frame, containing the attribute data
coordinates
signature(x = "SpatialPixelsDataFrame")
: retrieves coordinates
[
signature(x = "SpatialPixelsDataFrame")
: selects row(s) and/or attribute(s), and returns an
object of class
SpatialPixelsDataFrame
; rows refer here to the pixel
numbers, not grid lines. For selecting a square block in a grid, coerce to
a
SpatialGridDataFrame-class
first, and use
[
on that object
as.matrix
signature(x = "SpatialPixelsDataFrame")
: coerce to matrix
rbind
signature(x = "SpatialPixelsDataFrame")
: rbind-like method
plot
signature(x = "SpatialPixelsDataFrame", y = "missing")
: see
SpatialGridDataFrame-class
for details
data(meuse.grid) # only the non-missing valued cells
coordinates(meuse.grid) = c("x", "y") # promote to SpatialPointsDataFrame
gridded(meuse.grid) <- TRUE # promote to SpatialPixelsDataFrame
meuse.grid[["idist"]] = 1 - meuse.grid[["dist"]] # assigns new attribute
image(meuse.grid["idist"]) # note the single [
# toy example:
df = data.frame(z = c(1:6,NA,8,9),
xc = c(1,1,1,2,2,2,3,3,3),
yc = c(rep(c(0, 1.5, 3),3)))
coordinates(df) = ~xc+yc
gridded(df) = TRUE
image(df["z"])
# draw labels to verify:
cc = coordinates(df)
z=df[["z"]]
zc=as.character(z)
zc[is.na(zc)]="NA"
text(cc[,1],cc[,2],zc)
