You’ll now erase the buffer zones from the suitable vegetation patches to exclude these areas from the analysis.

To do so, expand the Overlay toolset located inside the Analysis Tools toolbox. Click and drag the Erase tool into the display window. Right-click the Erase tool in the model and click Open. Click the Input Features dropdown arrow.

Notice that you now have four variables at the top of the list of inputs as well as all the layers in the table of contents to choose from. When you drag data into a ModelBuilder window or when you set the data referenced by input or derived data elements within a tool’s dialog box, the elements created in the ModelBuilder window are variables that can be shared between processes.

Click the variable Suitable Vegetation from the dropdown list. Note the blue icon indicating that it is a variable. Click the Erase Features dropdown arrow and click the variable Roads Buffer. Leave the default location for the value of the Output Feature Class parameter and type “erase_output” for the name.

Leave the default value (blank) for the XY Tolerance parameter and leave the units as Feet. An appropriate default value will be calculated using the units of the spatial reference set for the output—in this case, in feet, as the input spatial reference units are in feet. All lines within the default XY Tolerance calculated will be considered coincident.

Click OK. The result feature class shows all vegetation patches that are away from existing roads and are suitable for habitation by the gnatcatcher.

Click Auto Layout then Full Extent to display all model elements in their default position within the display window. Right-click the erase_output derived data element and click Rename. Type “Suitable Vegetation (Minus Roads)” and click OK. Click the element Suitable Vegetation (Minus Roads) to select it, then click the blue handles and drag them to resize the element so all the text is displayed. Right-click the Suitable Vegetation (Minus Roads) derived data element and click Add To Display. Right-click the Erase tool and click Run.

It is good practice to save your changes to the model as you are building it. Click the Model menu and click Save.

The model is saved with its default name. You’ll rename the model later.