# Predictions of the spatial trend from an SpATS object

### Description

Takes a fitted `SpATS`

object produced by `SpATS()`

and produces predictions of the spatial trend on a regular two-dimensional array.

### Usage

1 | ```
obtain.spatialtrend(object, grid = c(100, 100), ...)
``` |

### Arguments

`object` |
an object of class |

`grid` |
a numeric vector with the number of grid points along the x- and y- coordinates respectively. Atomic values are recycled. The default is 100. |

`...` |
further arguments passed to or from other methods. Not yet implemented. |

### Details

For each spatial coordinate, `grid[k]`

equally spaced values between the minimum and the maximum are computed (k = 1, 2). The spatial trend is then predicted on the regular two-dimensional array defined by each combination of the x- and y- coordinate values.

### Value

A list with the following components:

`col.p` |
x-coordinate values at which predictions have been computed. |

`row.p` |
y-coordinate values at which predictions have been computed |

`fit` |
a matrix of dimension length(row.p) x length(col.p) with the predicted spatial trend. |

### See Also

`SpATS`

, `plot.SpATS`

, `predict.SpATS`

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | ```
library(SpATS)
data(wheatdata)
wheatdata$R <- as.factor(wheatdata$row)
wheatdata$C <- as.factor(wheatdata$col)
m0 <- SpATS(response = "yield", spatial = ~ SAP(col, row, nseg = c(10,20)),
genotype = "geno", fixed = ~ colcode + rowcode, random = ~ R + C,
data = wheatdata, control = list(tolerance = 1e-03))
spat.trend.1 <- obtain.spatialtrend(m0)
spat.trend.2 <- obtain.spatialtrend(m0, grid = c(10, 10))
colors = topo.colors(100)
op <- par(mfrow = c(1,2))
fields::image.plot(spat.trend.1$col.p, spat.trend.1$row.p, t(spat.trend.1$fit),
main = "Prediction on a grid of 100 x 100", col = colors, xlab = "Columns", ylab = "Rows")
fields::image.plot(spat.trend.2$col.p, spat.trend.2$row.p, t(spat.trend.2$fit),
main = "Prediction on a grid of 10 x 10", col = colors, xlab = "Columns", ylab = "Rows")
par(op)
``` |