Creating Buffered Layers

Buffer features of an existing layer for mapping and analysis.

A buffered layer contains a single multi-part polygon feature representing an area of a specified distance around a selection of features. The control is accessed through the Filter tab of the Layer Details pane. Buffers can also be used in conjunction with or as criteria for filters. This article describes how to create a buffered layer for a filtered selection of features. For more details on using buffers as criteria in creating a filtered selection, see Filtering and Joining Data.


How to Create a Buffered Layer

To create a buffered layer:

1. From the Layers list, click on the layer containing the features you would like to buffer. The layer is activated and the Layer Details pane appears.

2. Click the Filter tab of the Layer Details pane. You can also open the tab by clicking the Filter iconon the layer entry.

Filter, buffer, and join layer controls

3. To create a filtered selection of features that will be included in the buffered layer, clickAdd filter +. A searchable column list appears.

Buffered layers can be created for a maximum of 50,000 features. When working with datasets that exceed 50,000 features, you need to first apply filters to reduce the number of features to be included.

Searchable column list

4. Select one or more columns to filter on. Filter options for the selected columns will appear. You can apply filters to as many columns as you like. When you apply filters to multiple columns, features must satisfy the criteria for all columns. (This is akin to using an attribute query with an "and" operator.)

5. Specify filter criteria. Use the numeric and/or categorical filter options to select features.

Numeric data filters. You will see a slider bar and inputs for minimum and maximum values. You can use either to set a desired range for your selection. The map and data table are both dynamically updated to correspond to your criteria. Selected features are highlighted on the map with teal outlines, while the data table shows records for the selected features only.

Categorical (text) data filters. You will see a checklist of all values that occur within the layer. You can select one or more values; features with values that match any of the selected values (rather than all of the selected values) will be selected. (This is akin to using an attribute query with an "or" operator.)

Once you have applied filters to create a selection of features, the next step is to buffer them.

6. Click the buffer iconin the top right corner of the Filter control area. The Buffer controls appear.

Specifying a buffer

7. Enter a buffer distance. Distances can be specified in meters, feet, or miles. Buffers are measured "as the crow flies" from points, lines, or the edges of polygons. Buffers will not be drawn on the map until you save as a buffered layer.

8. To save your buffered selection as a layer, click Save as. A dialog box will appear.

9. Enter a name and description for the layer and click Ok. The buffered layer will be created and added to the Layer List. The new layer will be available to all users with access to the project.

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