geocausal (version 0.4.0)

get_hfr: Create a hyperframe

Description

`get_hfr()` takes a dataframe with time and location variables and generates a hyperframe with point patterns.

Usage

get_hfr(
  data,
  col,
  window,
  time_col,
  time_range,
  coordinates = c("longitude", "latitude"),
  combine = TRUE,
  input_crs = 4326,
  unit_scale = 1000
)

Value

A hyperframe is generated with rows representing time and columns representing the following: * The first column: time variable * The middle columns: ppp objects (see `spatstat.geom::ppp()`) generated for each subtype of events of interest * The last column (if `combine = TRUE`): ppp objects with all subtypes combined. This column is named as `all_combined`.

Arguments

data

dataframe. The dataframe must have time and location variables.

col

the name of the column for types of events of interest

window

owin object (for more information, refer to `spatstat.geom::owin()`). Must be a projected window (e.g., created via get_window with a target_crs specified). This function automatically detects the projection from the window and projects the event data accordingly.

time_col

the name of the column for time variable. Note that the time variable must be integers.

time_range

numeric vector. `time_range` specifies the range of the time variable (i.e., min and max of the time variable). The current version assumes that the unit of this time variable is dates.

coordinates

character vector. `coordinates` specifies the names of columns for locations. By default, `c("longitude", "latitude")` in this order. Note that the coordinates must be in decimal degree formats.

combine

logical. `combine` tells whether to generate output for all subtypes of events combined. By default, `TRUE`, which means that a column of ppp objects with all subtypes combined is generated in the output.

input_crs

the CRS of the input coordinates. Defaults to 4326 (WGS84 decimal degrees). The function will transform these to match the window projection

unit_scale

parameter to convert meters to kilometers

Examples

# Data
dat <- data.frame(time = c(1, 1, 2, 2),
                  longitude = c(43.9, 44.5, 44.1, 44.0),
                  latitude = c(33.6, 32.7, 33.6, 33.5),
                  type = rep(c("treat", "out"), 2))

# Hyperframe
get_hfr(data = dat,
        col = "type",
        window = iraq_window,
        time_col = "time",
        time_range = c(1, 2),
        coordinates = c("longitude", "latitude"),
        combine = FALSE)