Knowledge Base - Technical Articles
HowTo: Count the number of point features within a polygon
|Software:||ArcGIS - ArcEditor 8.3, 9.0, 9.1, 9.2, 9.3, 9.3.1, 10 ArcGIS - ArcInfo 8.3, 9.0, 9.1, 9.2, 9.3, 9.3.1, 10 ArcGIS - ArcView 8.3, 9.0, 9.1, 9.2, 9.3, 9.3.1, 10|
|Platforms:||Windows 2000, XP, 2003Server|
Instructions provided describe how to count the number of point features that are contained in a polygon.
Create a count field and a spatial join between the point shapefile and the polygon shapefile.
- In the attribute table of the point shapefile, create a field called 'Count' of type 'Short Integer'.
- Calculate the Count field equal to 1 by right-clicking on the field name > Field Calculator > Enter a 1 in the white dialog area below "Count = ", and click OK.
- Right-click the polygon shapefile and click Joins and Relates > Joins. Click the dropdown list and select 'Join data from another layer based on spatial location'.
- Specify the point shapefile from Step 1.
- Select the first bullet, each polygon is given a summary of the numeric attributes, for Step 2, and check the 'Sum' box.
- At Step 3, specify an output location and click OK.
- A polygon shapefile with the 'Count' field indicating how many point features lie within each polygon feature is now present.
Last Modified: 8/17/2011
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