near_repeat_analysis {rcrimeanalysis}

Near Repeat Analysis of Crime Incidents with Crime Linkage Output

Description

This function performs near repeat analysis for a set of incident locations. The user specifies distance and time thresholds which are utilized to search all other incidents and find other near repeat incidents. From this an adjacency matrix is created for incidents which are related under the thresholds. The adjacency matrix is then used to create an igraph graph which illustrates potentially related or linked incidents (under the near repeat thresholds).

Usage

near_repeat_analysis(
  data,
  epsg,
  dist_thresh = NULL,
  time_thresh = NULL,
  tz = NULL
)

Arguments

data

Data frame of crime or RMS data. See provided Chicago Data Portal example for reference

epsg

The EPSG Geodetic Parameter code for the area being considered. The EPSG code is used for identifying projections and performing coordinate transformations. If needed, the EPSG for an area can be found at https://spatialreference.org.

dist_thresh

The spatial distance (in meters) which defines a near repeat incident. By default this value is set to 1000 meters.

time_thresh

The temporal distance (in days) which defines a near repeat incident. By default this value is set to 7 days.

tz

Time zone for which the area being examined. By default this value is assigned as the same time zone of the system. For more information about time zones within R, see https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/timezones.

Value

Returns a list of all near repeat series identified within the input data as igraph graph objects. This list can be used to generate plots of each series and to discern the near repeat linkages between the crime incidents.

Author(s)

Jamie Spaulding, Keith Morris

Examples

data(crimes)
nr_data <- head(crimes, n = 1000) #truncate dataset for near repeat analysis
out <- near_repeat_analysis(data=nr_data,tz="America/Chicago",epsg="32616")