db.grid.fill {RGeostats}

R Documentation

Fill the empty cells of a Grid

Description

Fill the empty cells of a Grid

Usage

db.grid.fill(db, mode = 0, seed = 1321, radius = 1, radix="Grid.Fill",
		 modify.target=db.locmod())

Arguments

db	The db-class of grid type where the variable will be filled.
mode	Type of filling function. This depends on the dimension of the Grid. For a Space Dimension > 1, the type of filling is: 0 Moving average 1 Inverse squared distance 2 Interpolation by a linear plane For a 1-D regular grid, the type of filling is: 0 Linear interpolation 1 Cubic spline interpolation
seed	Random seed
radius	Neighborhood radius
radix	Radix of the name given to the variables storing the results in the target Db.
modify.target	Decides whether or not the newly created variables will have their locator defined or not. For more information, see db.locmod.

Details

The Z-variable defined on a grid is filled if necessary. When a cell is not defined, its value is derived by interpolation from its nearest neighbors. The procedure is performed by successive rings, starting from the periphery of the cells where the target variable is initially defined. This procedure is iterated until all the cells are filled. This procedure is meant to avoid spurious artefacts linked to strong uncontrolled extrapolation.

Value

The db-class of grid type where the target variable is filled.

Examples

# Example for ndim>1
grid = db.create(nx=c(100,100))
grid = simtub(,grid,model.create(vartype=4,range=20))
plot(grid,title="Reference map")
grid = db.rename(grid,grid$natt,"my.var")
grid = db.add(grid,my.new.var = ifelse(my.var > 1,NA,my.var))
grid = db.grid.fill(grid)
plot(grid,title="Reconstructed map")
rm(grid)

# Example in 1-D
db1D = db.create(nx=600,dx=0.01)
db1D = db.add(db1D,real=sin(db1D$x1))
data = rep(NA,db1D$nech)
index = sort(unique(floor(db1D$nech*runif(10))))
data[index] = db1D[index,"real"]
db1D = db.add(db1D,data)
plot(db1D,name.post="data",pch=19,col="red")
db1D = db.grid.fill(db1D,mode=1,modify.target=FALSE,radix="spline")
plot(db1D,add=TRUE,name="spline*")
db1D = db.grid.fill(db1D,mode=0,modify.target=FALSE,radix="linear")
plot(db1D,add=TRUE,name="linear*")
rm(db1D)

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