I have two Polygons, A and B, in two shapefiles.

Is there any automatic way to reshape the edge of Polygon A according to the edge of Polygon B?


Yes - use these two editing tools together:

The Reshape Feature tool lets you reshape a polygon by constructing a sketch over a selected feature. The feature takes the shape of the sketch from the first place the sketch intersects the feature to the last.

Tracing is a quick and accurate way of creating new segments that follow the shapes of other features. You can trace directly on top of a feature or apply an offset value. To trace, use either the Line or Polygon tool in conjunction with the Trace construction method on the palette on the Editor toolbar (or the Feature Construction mini toolbar).

  • There are several tools available that I use, depending on how complex the features are, and their overlaps and gaps. The reshape and trace method PolyGeo suggests is one of them. Others you might look at are Align to Shape, Replace Geometry, Split Polygons (split then delete overlap), Autocomplete polygon (add then merge), and as your title suggests moving vertices with snapping for the simplest.
    – johns
    Apr 3 '15 at 12:59
  • thanks, but i was asking about an automatic way to do that Apr 3 '15 at 14:08
  • Have you looked at the Snap Tool in ArcToolbox? If the differences are very small you might also look at the Integrate tool. There is a global snap polygon wizard in ET Geowizards but it is not one of the free tools.
    – johns
    Apr 3 '15 at 16:45
  • @johns I'd turn that first comment into your own answer. In particular Align to Shape and the Split/Autocomplete methods. Personally I don't think the others are quite as applicable, and your second comment's tools are also good solutions if looking to apply to an entire feature class/shapefile at once but maybe not just two polygons while editing.
    – Chris W
    Apr 3 '15 at 20:14
  • You made no mention of Trace in your question so I assumed that you were unaware that rather than entering each vertex manually with snapping that tool can be used to automate the process.
    – PolyGeo
    Apr 3 '15 at 20:21

One trick I use for this situation is to reshape A to overlap B in a quick, rough manner, snapping to the edge/vertices of B I want to start/end on and using a few quick vertices in between. Then I select B and on the Editor dropdown choose Clip, and you can cut A using B. Note that this will cut everything overlapping B that is visible/editable, so it won't work in all situations. Also note that it doesn't introduce vertices on B if you snap to the edge, so a coincidence topology check will fail.

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