The Aggregate Points tool uses area features to summarize a set of point features. The boundaries from the area feature are used to collect the points within each area and use them to calculate statistics. The resulting layer displays the count of points within each area.
Analysis using GeoAnalytics Tools
Analysis using GeoAnalytics Tools is completed using distributed processing across multiple ArcGIS GeoAnalytics Server machines and cores. GeoAnalytics Tools and standard feature analysis tools in Portal for ArcGIS have different parameters and capabilities. To learn more about the standard tool Aggregate Points, see aggregate points. To learn more about the differences between the tools, see Feature analysis tool differences.
Tornadoes are one of the most violent types of storms that occur 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 across the United States, but you need a better way to visualize your data within the boundaries of your choice. You can aggregate your tornado data into state and county boundaries and normalize your data by population to find the areas most affected by tornadoes.
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.
You can provide the area layer to use for analysis, or you can generate bins of a specified size and shape (hexagon or square) to aggregate into. 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 will be 2 times the height divided by the square root of 3. If you are aggregating into squares, the bin size is the height of the square, which is equal to the width.
Only areas that contain points will be returned, and resulting areas will be completely removed from the result layer.
The most basic aggregations will calculate a count of the number of points in each boundary. Statistics (count, sum, minimum, maximum, range, mean, standard deviation, and variance) can also be calculated on numerical fields, and statistics (count, any) can be calculated on string fields. The statistics will be calculated on each area separately.
Aggregate Points allows you to optionally analyze using time slices. Each time slice is analyzed independent of features outside of the time slice. To use time slicing, your input data must be time-enabled and represent an interval in time. When time slicing is applied, output features will be time intervals represented by the fields START_DATETIME and END_DATETIME.
Aggregate Points requires that your area layer is in a projected coordinate system.
If Use current map extent is checked, only the features that are visible within the current map extent will be analyzed. If unchecked, all input features in the input layer will be buffered, even if they are outside the current map extent.
Inputs must include a point layer. The area to aggregate into must be a provided area layer or bins. Lines and areas cannot be aggregated into areas using the Aggregate Points tool.
How Aggregate Points works
Variance is calculated using the following equation:
Standard deviation is calculated as the square root of the variance.
Point layers are summarized using only the point features intersecting the input boundary. The results are displayed in blue and can be symbolized using graduated symbols on the calculated statistics.
The following figure and table illustrate the statistical calculations of a point layer within district boundaries. The Population field was used to calculate the statistics (Count,Sum, Minimum, Maximum, Range, Mean, Standard Deviation, and Variance) for the layer. The Type field was used to calculate the statistics (Count and Any) for the layer.
|Numeric Statistic||Results District A|
|String Statistic||Results District A|
= Secondary School
The count statistic (for strings and numeric fields) counts the number of nonnull values. The counts of [0, 1, 10, 5, null, 6] = 5. The count of [Primary, Primary, Secondary, null] = 3.
A real-life scenario in which this analysis could be used is in determining the total number of students in each school district. Each point represents a school. The Type field gives the type of school (elementary, middle school, or secondary), and a student population field gives the number of students enrolled at each school. The calculations and results are given for District A in the table above. From the results, you can see that District A has 2,568 students. When running the Aggregate Points tool, the results would also be given for District B.
Use Aggregate Points to summarize points within areas. Other tools may be useful in solving similar but slightly different problems.
Map viewer analysis tools
If you are trying to summarize lines or areas into areas or bins, use the GeoAnalytics Tools Summarize Within.
If you are trying to summarize points, lines or areas using different spatial relationships, use the GeoAnalytics Tools Join Features.
If you are trying to summarize lines or areas, use the standard toolSummarize Within.
If you would like to aggregate points into areas using the standard analysis tools, see Aggregate Points.
ArcGIS Desktop analysis tools
The GeoAnalytics Tools Aggregate Points is available in ArcGIS Pro.