CRTsp {CRTspat}R Documentation

Create or update a "CRTsp" object


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


  x = NULL,
  design = NULL,
  geoscale = NULL,
  locations = NULL,
  kappa = NULL,
  mu = NULL



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.


list: an optional list containing the requirements for the power of the trial


standard deviation of random displacement from each settlement cluster center (for new objects)


number of locations in population (for new objects)


intensity of Poisson process of settlement cluster centers (for new objects)


mean number of points per settlement cluster (for new objects)


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.


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


{# Generate a simulated area with 10,000 locations
example_area = CRTsp(geoscale = 1, locations=10000, kappa=3, mu=40)

[Package CRTspat version 1.2.0 Index]