SpatialPixels: define spatial grid

Description

defines spatial grid by offset, cell size and dimensions

Usage

GridTopology(cellcentre.offset, cellsize, cells.dim)
SpatialPixels(points, tolerance = sqrt(.Machine$double.eps),
		proj4string = CRS(as.character(NA)), round=NULL, fuzz.tol=3)
SpatialGrid(grid, proj4string = CRS(as.character(NA)))
coordinatevalues(obj)
points2grid(points, tolerance = sqrt(.Machine$double.eps), round=NULL, fuzz.tol=3)
getGridIndex(cc, grid, all.inside = TRUE)
getGridTopology(obj)
areaSpatialGrid(obj)

Arguments

cellcentre.offset

numeric; vector with the smallest coordinates for each dimension

cellsize

numeric; vector with the cell size in each dimension

cells.dim

integer; vector with number of cells in each dimension

points

coordinates, object of class SpatialPoints-class

grid

grid topology; object of class GridTopology-class

tolerance

precision, used to which extent points are exactly on a grid

round

default NULL, otherwise a value passed to as the digits argument to round for setting cell size

fuzz.tol

default 3 - a tuning argument to attempt to detect fuzz - the ratio of row/col coordinates to unique row/col coordinates

proj4string

object of class CRS-class

obj

object of class or deriving from SpatialGrid-class

numeric matrix with coordinates

all.inside

logical; if TRUE and cc points fall outside the grid area, an error message is generated; if FALSE, NA values are generated for such points

Value

GridTopology returns a value of class GridTopology-class; SpatialGrid returns an object of class SpatialGrid-class
coordinatevalues returns a list with the unique x-coordinates, the unique y-coordinate, etc. instead of the coordinates of all grid cells
SpatialGrid returns an object of class SpatialGrid-class.
points2grid returns the GridTopology-class from a set of points.
getGridIndex finds the index of a set of point coordinates in a given grid topology, and depending on all.inside setting, generates NA or an error message if points are outside the grid domain.
getGridTopology returns the slot of class GridTopology-class from obj.
areaSpatialGrid returns the spatial area of (the non-missing valued cells of) the grid. For objects of class SpatialGridDataFrame-class the area refers to cells where any (one or more) of the attribute columns are non-missing valued.

Examples

Run this code

x = GridTopology(c(0,0), c(1,1), c(5,4))
class(x)
x
summary(x)
coordinates(x)
coordinates(GridTopology(c(0,0), c(1,1), c(5,4)))
coordinatevalues(x)
data(meuse.grid)
coordinates(meuse.grid) <- c("x", "y")
points2grid(meuse.grid)
data(meuse.grid)
set.seed(1)
meuse.grid$x <- meuse.grid$x + rnorm(length(meuse.grid$x), 0, 0.002)
meuse.grid$y <- meuse.grid$y + rnorm(length(meuse.grid$y), 0, 0.002)
coordinates(meuse.grid) <- c("x", "y")
points2grid(meuse.grid, tolerance=0.76, round=1)
data(meuse.grid)
a <- which(meuse.grid$x == 180140)
b <- which(meuse.grid$x == 180180)
c <- which(meuse.grid$x == 179260)
d <- which(meuse.grid$y == 332460)
e <- which(meuse.grid$y == 332420)
f <- which(meuse.grid$y == 330740)
meuse.grid <- meuse.grid[-c(a, b, c, d, e, f),]
coordinates(meuse.grid) <- c("x", "y")
points2grid(meuse.grid)
data(meuse.grid)
set.seed(1)
meuse.grid$x <- meuse.grid$x + rnorm(length(meuse.grid$x), 0, 0.002)
meuse.grid$y <- meuse.grid$y + rnorm(length(meuse.grid$y), 0, 0.002)
meuse.grid <- meuse.grid[-c(a, b, c, d, e, f),]
coordinates(meuse.grid) <- c("x", "y")
points2grid(meuse.grid, tolerance=0.69, round=1)

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