Summary

Uses a series of distance and time values to classify incidents as originators, repeats, or near-repeats, and to identify potential space and time relationships between incidents.

Usage

• The Input Features must be a point feature class or shape file with a date field, representing the locations of incidents. This dataset must be in a projected coordinate system.
• The tool will use all points with date values. Incidents without valid dates will be excluded and a warning message will print to the screen listing the skipped incidents.
• This tool will honor a selected set of features. When the Input Features contain a selection, only the selected features will be considered when classifying features and building connections.
• Incidents are classified as O (originator), NR (near-repeat), or R (repeat) according to their proximity to each other in space and time using each combination of the specified spatial and temporal band values, and the specified repeat distance.
  • Incidents are classified as originators if they are the originator of at least one other incident and have no preceding incidents within the current spatial and temporal ranges.
  • Incidents are classified as near-repeat incidents when they follow a previous repeat, near-repeat, or originating incident within the current spatial and temporal ranges, and do not meet the criteria to be classified as a repeat incident.
  • Incidents are classified as repeat incidents when they occur within the specified repeat distance and the current temporal range. An incident that meets the requirements for both a repeat and a near-repeat incident is classified as a repeat.
  • Incidents that do not meet the criteria for any of the above are left unclassified.
• The tool will append one field for each spatial band-temporal band combination to the Input Features feature class. These fields are populated with the classification values for each incident within each set to spatial and temporal ranges.

  For example, if a repeat distance of 1 map unit, spatial bands of 100 and 200 map units, and temporal bands of 7 and 14 days are specified, the tool will append 6 fields.

  • s1t7 : Classification of incidents that are originators of repeat incidents occurring no more than 7 days later, and incidents that occurred within the repeat distance and 7 days of a previous incident.
  • s1t14 : Classification of incidents that are originators of repeat incidents occurring no more than 14 days later, and incidents that occurred within the repeat distance and 14 days of a previous incident.
  • s100t7 : Classification of incidents that are originators of repeat and near-repeat incidents occurring no more than 7 days later, and incidents that occurred within 100 map units and 7 days of a previous incident.
  • s100t14 : Classification of incidents that are originators of repeat and near-repeat incidents occurring no more than 14 days later, and incidents that occurred within 100 map units and 14 days of a previous incident.
  • s200t7 : Classification of incidents that are originators of repeat and near-repeat incidents occurring no more than 7 days later, and incidents that occurred within 200 map units and 7 days of a previous incident.
  • s200t14 : Classification of incidents that are originators of repeat and near-repeat incidents occurring no more than 14 days later, and incidents that occurred within 200 map units and 14 days of a previous incident.
• The tool also appends a field called ZVALUE with values representing the number of days between each incident and the smallest date value in the dataset. These values can be used to visualize the time sequence of incidents in ArcGIS Pro so that oldest incidents appear near the ground and more recent incidents appear further from the ground.
• If any of these fields exist in the dataset already, the values in that field are overwritten.
• This tool creates three outputs:
  1. Appends classification fields to the Input Features dataset.
  2. Creates a line feature class that is populated with z-enabled line features representing the potential relationships between repeat and near-repeat incidents and their originators. The z values for each vertex correspond to the ZVALUE field value for the incident that occurs at that vertex.
  3. Creates a CSV summary report with the number of incidents processed, the counts and proportions of incidents that fall within each spatial and temporal band combination, and the estimated half-life and half-distance values which can be used as inputs for the Calculate Prediction Zones tool.
• All distances are calculated using geodesic measurements.
• This tool requires an ArcGIS for Desktop Advanced license.

Parameters