Aggregate Points (Standard Feature Analysis)

Summary

Uses a layer of point features and a layer of polygon features to determine which points fall within each polygon's area. After determining this point-in-polygon spatial relationship, statistics about all points in the polygon are calculated and assigned to the area.

The most basic statistic is the count of the number of points within the polygon, but you can get other statistics as well. For example, if your points represented coffee shops and each point has a TOTAL_SALES attribute, you can get statistics like the sum of all TOTAL_SALES within the polygon, or the minimum or maximum TOTAL_SALES value, or the standard deviation of all sales within the polygon.

Illustration

Usage

• Aggregate Points is designed to collect and summarize point features within a set of boundaries. The input parameters must include points to be aggregated and aggregation areas.

• The Keep boundaries with no points box is checked by default. When the box is checked, all of the areas used in the analysis will be included in the result, regardless of the location of points. Areas with no points will be empty and have a count of 0. When the box is unchecked, the areas with no points are completely removed from the result layer. Unchecking the box may have a significant effect on the result areas.

  

  The difference in result layers when boundaries with no points are kept (left) or not kept (right)

• The most basic aggregations will calculate a count of the number of points in each boundary. Basic statistics (sum, minimum, maximum, average, and standard deviation) can also be calculated on numerical fields. The statistics will be calculated on each area separately.

• Statistical calculations can also be grouped using a field with categorical values. When statistics are grouped by a field, the statistics are calculated for both the area as a whole and for each group. Both statistics can be viewed in the result layer's pop-up. The overall statistics are given numerically and the grouped statistics are given in chart form within the pop-up. A summary table listing each feature and statistic by group field value will also be created. The Add minority, majority check box will return the groups with the lowest and highest counts and the Add percentages check box will return the percentage of points in the minority and majority groups.

• Point layers are summarized using only the point features within the input boundary. The results will be displayed using graduated symbols.

  The figure and table below explain the statistical calculations of a point layer within a hypothetical boundary. The Population field was used to calculate the statistics (Sum, Minimum, Maximum, Average, and Std Deviation) for the layer.

  

  Point layers are summarized using only points located within the boundary layer. An example attribute table is displayed above with values to be used in hypothetical statistic calculations.

  Statistic	Results District A
  Sum	280 + 408 + 356 + 361 + 450 + 713 = 2,568
  Minimum	Minimum of [280, 408, 356, 361, 450, 713] = 280
  Maximum	Maximum of [280, 408, 356, 361, 450, 713] = 713
  Average	2,568/6 = 428
  Std Deviation	= 150.79

Parameters

Dialog

Label	Explanation	Data Type
Input Points	The point features that will be aggregated into the polygons in the polygon layer.	Feature Set
Aggregating Polygons	The polygon features (areas) into which the input points will be aggregated.	Feature Set
Output Name	The name of the output layer to create on your portal.	String
Keep boundaries with no points (Optional)	Specifies whether the polygons that have no points within them should be returned in the output. Checked—Keep polygons that have no points. This is the default. Unchecked—Do not return polygons with no points in the output.	Boolean
Summary Fields (Optional)	A list of field names and statistical summary type that you wish to calculate for all points within each polygon. The count of points within each polygon is always returned. The following statistic types are supported: Sum—The total value. Minimum—The smallest value. Max—The largest value. Mean—The average or mean value. Standard deviation—The standard deviation.	Value Table
Group By Field (Optional)	A field name in the pointLayer. Points that have the same value for the group by field will have their own counts and summary field statistics. You can create statistical groups using an attribute in the analysis layer. For example, if you are aggregating crimes to neighborhood boundaries, you may have a Crime_type attribute with five different crime types. Each unique crime type forms a group, and the statistics you choose will be calculated for each unique value of Crime_type. When you choose a grouping attribute, two results are created: the result layer and a related table containing the statistics.	Field
Add minority and majority attributes (Optional)	This Boolean parameter is applicable only when a Group By Field is specified. If checked, the minority (least dominant) or the majority (most dominant) attribute values for each group field within each boundary are calculated. Two new fields are added to the output layer prefixed with Majority_ and Minority_. Unchecked—Do not add minority and majority fields. This is the default. Checked—Add minority and majority fields.	Boolean
Add percentage (Optional)	This Boolean parameter is applicable only when a Group By Field is specified. If checked, the percentage count of points for each unique Group By Field value is calculated. A new field is added to the output group summary table containing the percentages of each attribute value within each group. If Add minority and majority attributes is true, two additional fields are added to the output containing the percentages of the minority and majority attribute values within each group. Unchecked—Do not add percentage fields. This is the default. Checked—Add percentage fields.	Boolean

Derived Output

Label	Explanation	Data Type
Output Layer	The output layer.	Feature Set
Output Group Layer	The output table that summarizes the groups from the Group By Field.	Record Set

Python

arcpy.sfa.AggregatePoints(pointLayer, polygonLayer, outputName, {keepBoundariesWithNoPoints}, {summaryFields}, {groupByField}, {minorityMajority}, {percentPoints})

Name	Explanation	Data Type
pointLayer	The point features that will be aggregated into the polygons in the polygon layer.	Feature Set
polygonLayer	The polygon features (areas) into which the input points will be aggregated.	Feature Set
outputName	The name of the output layer to create on your portal.	String
keepBoundariesWithNoPoints (Optional)	Specifies whether the polygons that have no points within them should be returned in the output. KEEP_EMPTY —Keep polygons that have no points. This is the default. REMOVE_EMPTY —Do not return polygons with no points in the output.	Boolean
summaryFields [[Field, Statistic],...] (Optional)	A list of field names and statistical summary type that you wish to calculate for all points within each polygon. The count of points within each polygon is always returned. The following statistic types are supported: SUM—The total value. MIN—The smallest value. MAX—The largest value. MEAN—The average or mean value. STD—The standard deviation.	Value Table
groupByField (Optional)	A field name in the pointLayer. Points that have the same value for the group by field will have their own counts and summary field statistics. You can create statistical groups using an attribute in the analysis layer. For example, if you are aggregating crimes to neighborhood boundaries, you may have a Crime_type attribute with five different crime types. Each unique crime type forms a group, and the statistics you choose will be calculated for each unique value of Crime_type. When you choose a grouping attribute, two results are created: the result layer and a related table containing the statistics.	Field
minorityMajority (Optional)	This Boolean parameter is applicable only when a groupByField is specified. If true, the minority (least dominant) or the majority (most dominant) attribute values for each group field within each boundary are calculated. Two new fields are added to the output layer prefixed with Majority_ and Minority_. NO_MIN_MAJ —Do not add minority and majority fields. This is the default. ADD_MIN_MAJ —Add minority and majority fields.	Boolean
percentPoints (Optional)	This Boolean parameter is applicable only when a groupByField is specified. If set to ADD_PERCENT, the percentage count of points for each unique groupByField value is calculated. A new field is added to the output group summary table containing the percentages of each attribute value within each group. If minorityMajority is true, two additional fields are added to the output containing the percentages of the minority and majority attribute values within each group. NO_PERCENT —Do not add percentage fields. This is the default. ADD_PERCENT —Add percentage fields.	Boolean

Derived Output

Name	Explanation	Data Type
aggregatedLayer	The output layer.	Feature Set
groupSummary	The output table that summarizes the groups from the Group By Field.	Record Set

Environments

Output Coordinate System, Extent, Current Workspace

Licensing information

• Basic: Requires your account in ArcGIS Enterprise to have the Perform Analysis privilege
• Standard: Requires your account in ArcGIS Enterprise to have the Perform Analysis privilege
• Advanced: Requires your account in ArcGIS Enterprise to have the Perform Analysis privilege