How To: Group a select number of points in a shapefile based on proximity


The instructions provided describe how to group a select number of points in a shapefile based on proximity in ArcMap.


There are two methods to do this. In Method A, the Grouping Analysis tool is used to classify features in a group to be as similar as possible, and groups which are as different as possible. In Method B, use the Select By Lasso tool to manually select the desired features.

Users can apply Method A if Method B cannot be carried out and vice versa.

Method A
1. Navigate to ArcToolbox > Spatial Statistics Tools > Mapping Clusters > Grouping Analysis.

2. Fill out the following parameters in the Grouping Analysis dialog box.

• Input features: The feature class or feature layer for which users want to create groups.
• Unique ID Field: An integer field containing a unique identifier for every feature in the input feature class.
• Output Feature Class: Specifies the name and location for the new output feature class.
• Number of Groups: The number of groups to create. The Output Report parameter is disabled for more than 15 groups.
• Analysis Fields: A list of fields to be used to distinguish one group from another.
• Spatial Constraints: Specifies if and how spatial relationships among features should constrain the groups created.

3. Click OK. The features in a feature class are grouped based on attributes that are as similar as possible.

Method B

1. Navigate to the Tools toolbar, and click the Select Features drop-down > Select By Lasso to manually select the desired points.

To add more points to an existing selection, hold down the SHIFT key when selecting features. To remove feature(s), hold down the SHIFT key and click the previously selected features.

To remove all selected features, click the Clear Selected Features tool
on the Tools toolbar, or click a non-selectable feature belonging to a layer.

2. To select the desired points, click and drag the tool to specify the size of the selection extent.

3. Right-click the layer in the Table Of Contents > Data > Export Data to save the selected points as a shapefile.

4. Determine the output of the exported data. Click OK.

If a warning on adding the exported data to the map as a layer is displayed, click Yes.

The selected points are added as a shapefile.

5. To remove the unselected points, remove the shapefile from the Table Of Contents by right-clicking the layers > Remove.
The Select By Polygon tool can also be used to select the desired features, and steps 1 to 5 can be followed to produce the same result.


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