Exercise 2: Use an overlay to compare two layers

Compare the two layers you added in the previous exercise. The overlay shows you which parts of the enterprise zone lie within the flood zone.

To use an overlay to compare the two layers

1. Click Analyze tab Feature panel Feature Overlay
2. In the Sources and Overlay Type window of the Overlay Analysis dialog box, do the following:
   • For Source, select E_zone (Polygons).
   • For Overlay, select floodzone (Polygons).
   • For Type, select Intersect.
   • Click Next.
3. In the Set Output And Settings window of the Overlay Analysis dialog box, do the following:
   • Enter a location for the overlay layer SDF file.
   • Enter a name for the layer. This name appears in Display Manager.
   • For Sliver Tolerance, select Don’t Remove Slivers.

     Slivers are tiny polygons that can result from the overlay procedure. If you want to remove slivers, click Suggest to see a reasonable setting for sliver removal.

   • Leave the remaining settings as they are and click Finish.
     

     The map now displays the two original layers and a new layer, representing the overlay.

4. Click the Display Manager tab on the Task Pane.
5. Deselect the boxes for the original flood zone and enterprise zone layers, so that only the overlay layer displays in the map.
   

   Hide all the layers except the overlay.

6. Save the map.

To continue this tutorial, go to Exercise 3: Add and style a road layer.