# mkpredgrid2d: Make prediction grid In geoBayes: Analysis of Geostatistical Data using Bayes and Empirical Bayes Methods

## Description

This function creates a grid for prediction.

## Usage

 ```1 2``` ```mkpredgrid2d(pnts.x, pnts.y, par.x, par.y, isby = FALSE, chull = FALSE, exf = 1) ```

## Arguments

 `pnts.x` x coordinate of the domain. Could also be a two-column matrix containing the x and y coordinates `pnts.y` y coordinate of the domain. Should be omitted or set to `NULL` if the argument `pnts.x` is a two-column matrix. `par.x` A scalar parameter for the x component of the new grid. This parameter corresponds to either the `by` or the `length.out` arguments of the function `seq`. Could also be a vector of two elements containing the parameter for x and y. `par.y` As in `par.x` for the y component of the new grid. Should be omitted or set to `NULL` if the argument `par.x` is a two-dimensional vector. `isby` If `TRUE`, the arguments `par.x` and `par.y` correspond to the `by` argument of the function `seq`, otherwise they correspond to `length.out`. `chull` Whether to calculate the convex hull of the points. Set this to `TRUE` if `pnts.x` and `pnts.y` denote the sampled locations. If they correspond to the borders of the domain, it is recommended to set this to `FALSE`. `exf` An expansion factor of the convex hull of `cbind(pnts.x, pnts.y)`. Must be positive. If larger or smaller than 1, the convex hull is respectively expanded or contracted.

## Details

If `chull` this function first calculates the convex hull of the points. If `exf` is not 1 the borders are expanded. Then the function calls `point.in.polygon` to select points that fall inside the borders.

## Value

A list with components

• `grid` A two-column matrix with the prediction grid.

• `xycoord` A list with components "x" and "y" containing the sequence of points used to create the grid.

• `xygrid` A matrix with the full square grid derived from `xycoord`.

• `borders` The (expanded) borders of the domain.

• `inxygrid` A logical vector indicating which rows of `xycoord` fall inside `borders`, and therefore correspond to the `grid`.

## See Also

`pred_grid`

## Examples

 ```1 2 3 4 5 6 7 8 9``` ```## Not run: data(rhizoctonia) predgrid <- mkpredgrid2d(rhizoctonia[c("Xcoord", "Ycoord")], par.x = 100, chull = TRUE, exf = 1.2) plot(predgrid\$borders, type = "l") # Domain for prediction points(predgrid\$grid, pch = 20, cex = .3) # Prediction locations points(rhizoctonia[c("Xcoord", "Ycoord")]) # Observed locations ## End(Not run) ```

### Example output ```
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geoBayes documentation built on May 2, 2019, 3:14 a.m.