Creating adjoining polygons

If you are creating polygons of land uses, soils, counties, or property ownership, for example, you often need to create polygons next to one another. The polygons should share a border, but you want to avoid digitizing the border twice or having overlaps or spaces between polygons. You can use the Auto-Complete Polygon construction tool when creating new polygons to help ensure that your data forms a continuous fabric. With Auto-Complete Polygon, you can digitize a new polygon that adjoins an existing polygon, using the existing polygon's geometry and the edit sketch to define the edges of the new polygon.


Creating features with the Auto-Complete Polygon tool inserts vertices on existing features to maintain coincidence between adjacent features. Vertices are added to the existing polygon at the locations where the sketch of the new feature crosses the existing feature.

  1. Click a polygon feature template in the Create Features window.
  2. Click the Auto-Complete Polygon tool Auto Complete Polygon on the Create Features window.
  3. Starting from the boundary of an existing polygon in the same layer, digitize a boundary of the new polygon that will share a boundary with the existing polygon.
  4. To change the shape of the sketch segment, click a construction method type on the Editor toolbar or on the Feature Construction mini toolbar. Segments can be created using a variety of methods—for example, as straight lines, with curves, or traced from the shapes of other features. You can also use keyboard shortcuts or right-click to access a menu of commands to help you place vertices in the sketch.
  5. You can either snap the sketch to the edge of the existing polygon or finish the sketch just inside the existing polygon. The sketch must cross (or touch) the existing polygon edge at least two times for the new polygon to be created.