Geographic Information Systems (GIS) Services Frequently Asked Questions:

How do I use a subset of the features in a layer?

I've found some data I'd like to use, but it covers areas that are outside of my area of interest. How do I use a subset of the features in a layer?

One way to display a subset of features is to use a definition query.

When a layer's properties include a definition query, only the features that meet the criteria defined by that query are displayed. For example, if you have a layer depicting county boundaries for the entire United States, and you are only interested in North Carolina counties, the definition query "STATE_NAME" = 'North Carolina' would limit the features displayed to those with a state name attribute of North Carolina.

If there are multiple states in your area of interest, you would use a query like this: "STATE_NAME" = 'North Carolina' OR "STATE_NAME" = 'South Carolina' This query would limit the features displayed to those with a state name attribute of North Carolina or a State Name attribute of South Carolina.

Note that there needs to be attributes in the attribute table that can be used to build a useful query.

For more information, see Displaying a subset of features in a layer.

For help constructing queries, see About building an SQL expression.

Another way to work with only part of a layer is to select the features you want to include, and then export them to a new layer. Two easy ways to select features include using select by location, and select by attributes.

Once you have selected the features you want to use, you can then Export Features to a new layer. Only the selected features will be included in the new layer.

One other way to create a subset of data is to use the clip tool in ArcToolbox.

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