# Create or update a `"CRTsp"`

object

`CRTsp.Rd`

`CRTsp`

coerces data frames containing co-ordinates and location attributes
into objects of class `"CRTsp"`

or creates a new `"CRTsp"`

object by simulating a set of Cartesian co-ordinates for use as the locations in a simulated trial site

## Usage

```
CRTsp(
x = NULL,
design = NULL,
geoscale = NULL,
locations = NULL,
kappa = NULL,
mu = NULL,
geometry = "point"
)
```

## Arguments

- x
an object of class

`"CRTsp"`

or a data frame containing locations in (x,y) coordinates, cluster assignments (factor`cluster`

), and arm assignments (factor`arm`

). Optionally specification of a buffer zone (logical`buffer`

); any other variables required for subsequent analysis.- design
list: an optional list containing the requirements for the power of the trial

- geoscale
numeric: standard deviation of random displacement from each settlement cluster center (for new objects)

- locations
integer: number of locations in population (for new objects)

- kappa
numeric: intensity of Poisson process of settlement cluster centers (for new objects)

- mu
numeric: mean number of points per settlement cluster (for new objects)

- geometry
with valid values

`'point'`

(the default, corresponding to point locations),`'triangle'`

,`'square'`

and`'hexagon'`

corresponding to grids constructed from pixels of regular polygons.

## Value

A list of class `"CRTsp"`

containing the following components:

`design` | list: | parameters required for power calculations |

`geom_full` | list: | summary statistics describing the site |

`geom_core` | list: | summary statistics describing the core area (when a buffer is specified) |

`trial` | data frame: | rows correspond to geolocated points, as follows: |

`x` | numeric vector: x-coordinates of locations | |

`y` | numeric vector: y-coordinates of locations | |

`cluster` | factor: assignments to cluster of each location | |

`arm` | factor: assignments to `"control"` or `"intervention"` for each location | |

`nearestDiscord` | numeric vector: Euclidean distance to nearest discordant location (km) | |

`buffer` | logical: indicator of whether the point is within the buffer | |

`...` | other objects included in the input `"CRTsp"` object or data frame |

## Details

If a data frame or `"CRTsp"`

object is input then the output `"CRTsp"`

object is validated,
a description of the geography is computed and power calculations are carried out.

If `geoscale, locations, kappa`

and `mu`

are specified then a new trial dataframe is constructed
corresponding to a novel simulated human settlement pattern. This is generated using the
Thomas algorithm (`rThomas`

) in `spatstat.random`

allowing the user to defined the density of locations and degree of spatial clustering.
The resulting trial data frame comprises a set of Cartesian coordinates centred at the origin.

## Examples

```
{# Generate a simulated area with 10,000 locations
example_area = CRTsp(geoscale = 1, locations=10000, kappa=3, mu=40)
summary(example_area)
}
#> Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]): namespace 'spatstat.utils' 3.0-4 is already loaded, but >= 3.0.5 is required
```