I'm surprised that ArcScan cannot automatically vectorize meaningful polygon from a raster file. In the mode of interactive vectorization, you can create both polylines and polygons by tracing raster cells. However, in the automatic vectorization mode, you can only generate polylines. Well, you still can set a small value for maximum line width to generate a polygon for using outline vectorization method to generate polygons. But those polygons are not the same kind of polygons can be generated in interactively tracing. Use the tutorial dataset of land parcels, for example, the polygons I want is the ones represent each parcel (the ParcelPolygon.jpg as attached), not a polygon enclose the boundary (like the attached BoundaryPolygon.jpg).
Why ESRI designed ArcScan like this, one can only automatically generate polylines but meaningful polygons? Who thinks those boundary polygons are more useful than the parcel polygons? If such method is available in interactively tracing option, not in automatic vectorization? Is there anybody from ESRI can clarify this? You may argue that you can convert the polylines to polygons using other tools. Well, that's true but I still think it is convenient to have this functions available both in interactive and automatic vectorization mode. BTW, once you use those conversion tools outside the same context, you may face errors and information loss during the conversion process. The new addition will make ArcScan complete.