Aggregate Points

Available in big data analytics.

The Aggregate Points tool collects and summarizes point features within area features. The boundaries from the area features are used to collect the points within each area; they are then used to calculate statistics. The resulting layer contains the count of points within each area as well as summary calculations.

Workflow diagram

Example

The following is an example use case for the tool:

Tornadoes are a violent type of storm that occurs in the United States. You want to know the effect of tornadoes, including loss of life, injuries, property damage, and financial loss, in each state and county. You have access to tornado locations, but you need a better way to visualize the data within certain areas. You can aggregate the tornado data into state and county boundaries and normalize the data by population to find the areas most affected by tornadoes.

Usage notes

Keep the following in mind when working with the tool:

• The output layer is always a polygon layer. Only the polygon bins or features where points occur are returned.
• You can provide the area layer for the analysis, or generate bins of a specified size and shape (hexagon or square) to aggregate point features. The bin size specifies how large the bins are. If you are aggregating into hexagons, the size is the height of each hexagon and the width of the resulting hexagon is two times the height divided by the square root of three. If you are aggregating into squares, the bin size is the height of the square, which is equal to the width.

  

• If time is enabled on the target data, you can apply time steps to the analysis.
• The most basic aggregations calculate the number of points in each area. Statistics—including Count, Sum, Min, Max, Range, Mean, and Standard Deviation—can be calculated on numerical fields, and statistics, such as Count and Any, can be calculated on string fields. The statistics are calculated in each area separately.

  The following are example return values:

  • When Count is applied to a field, it returns a count of the nonnull values present in the field.
  • When Any is applied to a string field, it returns a single string present in the field.
• The Aggregate Points tool allows you to analyze using time steps. Each time step is analyzed independently of features outside of the time step. To use time steps, the target data must be time enabled and represent an instant in time. When time steps are used, output features are time intervals represented by the StartTime and EndTime fields.
• If you specify the time step Interval, Repeat, or Alignment option and time is not enabled on the data, an error occurs when the tool is run.
• The time step options can be a date and time value or a date-only value; it cannot be a time-only value.
• The Aggregate Points tool requires that the target data is projected or that the target data is set to a projected coordinate system. If the target data is not in a projected coordinate system and you do not set one, the tool automatically applies the World Cylindrical Equal Area projected coordinate system to the data you are analyzing.

Parameters

The following are the parameters for the tool:

Parameter	Description	Data type
Target data	The point features that are aggregated into bins or polygons.	Features
Join data (optional)	The polygon features the target data is aggregated with. A join data source is required to aggregate data into polygons.	Features
Aggregate points into	Specifies how the target data will be aggregated. The options are the following Bins—Target data will be aggregated into square or hexagon bins. The Target data parameter is required for this option. Polygons—Target data will be aggregated into polygons from the join data. The Join data parameter is required for this option.	String
Bin type (optional)	The bin shape that will be used to create the bins. Options are Square (the default) and Hexagon. If a source is connected to the join port, this parameter is not available. Note: This parameter is only available if the Aggregate points into (Polygon or Bin) parameter is set to Bins.	String
Bin size (optional)	The distance interval that represents the bin size into which the target data will be aggregated. For square bins, the bin size represents the height of a square. For hexagon bins, the bin size represents the height between two parallel sides. If a source is connected to the join port, this parameter is not available. Note: This parameter is only available if the Aggregate points into (Polygon or Bin) parameter is set to Bins.	String
Interval (optional)	The duration of the time step. Use this option only if the target data is time enabled and represents an instance in time. Learn how time steps work	String
Repeat (optional)	Specifies how often the time-step interval occurs. Use this option only if the target data is time enabled and represents an instance in time.	String
Alignment (optional)	The reference time with which to align the time steps. The default is January 1, 1970, at 12:00 a.m. Check this parameter's check box to choose a date and time range. Use this option only if the target data is time enabled and represents an instance in time.	Int64
Summary fields (optional)	The statistics that will be calculated for specified fields. Different statistics are available depending on whether the specified field is a string, numeric, or date field. Any—Calculates a sample string from a field of data type string. Count—Calculates the number of nonnull values. It can be used on numeric fields or strings. The count of [null, 0, 2] is 2. Count (distinct)—Calculates the number of distinct, nonnull values. It can be used on numeric fields or strings. The count distinct result of [null, 4, 3, 4] is 2. Sum—Calculates the sum of numeric values in a field. The sum of [null, 1, 3] is 4. Square Sum—Calculates the sum of squared differences between each observation and the overall mean. The sum of squares of [null, 2.2, 3.1, 4.7] is 3.206. Min—Calculates the minimum value of a numeric field. The minimum of [0, 2, null] is 0. Max—Calculates the maximum value of a numeric field. The maximum value of [0, 2, null] is 2. Mean—Calculates the mean of numeric values. The mean of [0,2, null] is 1. Range— Calculates the range of a numeric field by subtracting the minimum value from the maximum value. The range of [0, null, 1] is 1. The range of [null, 4] is 0. Variance—Calculates the variance of a numeric field in a track. The variance of [1] is null. The variance of [null, 1,1,1] is 1. Standard Deviation—Calculates the standard deviation of a numeric field. The standard deviation of [1] is null. The standard deviation of [null, 1,1,1] is 1.	String

Output layer

The output layer contains all original fields from the area features and the COUNT field. The COUNT field represents the number of point features from the target data aggregated into this polygon feature. The data type of the COUNT field is Float64. If you configure summary fields, those fields are also calculated for the output layer.

Consideration and limitation

Lines and polygons cannot be aggregated within boundaries using the Aggregate Points tool.