# Plot grid-based residuals

### Description

`plot.gridresid`

is a generic function for plotting grid-based residuals.

### Usage

1 2 | ```
## S3 method for class 'gridresid'
plot(x, ..., col.key = rev(heat.colors(100)), cutoffs = NULL)
``` |

### Arguments

`x` |
A “ |

`...` |
Arguments for use with |

`col.key` |
A vector of colors in hexadecimal format. |

`cutoffs` |
A vector of cut points for assigning the colors in |

### Details

`cutoffs`

must be a vector of increasing values of the same length as `col.key`

plus 1. `cutoffs`

divides the residual values in `x$residuals`

into a number of intervals equal to the number of colors in `col.key`

. The colors are assigned to the intervals in order, e.g. the first color in `col.key`

will be plotted in the bins defined by the spatial grid in `x$grid`

that contains a residual that falls anywhere in the first interval (lower bound inclusive, upper bound exclusive).

Default `col.key`

is a vector of 100 `heat`

colors in reverse. Default `cutoffs`

is a vector of 101 equally spaced points that range from the minimum residual in `x$residuals`

, minus a very small number, to the maximum residual, plus a very small number.

### Note

The default `col.key`

and `cutoffs`

may not be useful if the residuals are highly skewed. In this case, there should be more values in `cutoffs`

where the residuals are most dense.

These are simply default plots for quick illustration of the residuals, and may or may not be useful for detailed analysis of the residuals.

### Author(s)

Robert Clements

### See Also

`gridresid`

, `image`

### Examples

1 2 3 4 5 6 7 | ```
data(gresiduals)
plot(gresiduals)
hist(gresiduals$residuals)
cutoffs = c(seq(-2.74, -1.01, length.out = 15),
seq(-1, 1, length.out = 70), seq(1, 3.83, length.out = 16))
plot(gresiduals, cutoffs = cutoffs)
``` |