Construct Polygons (with Use existing features in target) changes existing features

[JohnHansen]

Greetings,

We use the Construct Polygons tool with the Use existing features in target option (ArcGIS 10.1 SP1, Sql Server 2008 SP2 versioned GDB) to construct parcel polygons using selected line features from another feature class which exists in the same geodatabase/feature dataset. We have no database topologies set, and do not use map topologies. I find that the tool sometimes (most times?) will slightly change the geometry of the existing features used to construct the new polygons. Afterwards, when using the Version Changes tool on the edit version, these adjacent (existing) polygon feature(s) will be listed, but will sometimes have no values (including Shape/SHAPE.Area/SHAPE.Len) displayed in bold to signify any change to the feature. Does this tool, when used with this option, set up a map topology which may effect (change) the existing features? The documentation does not explictly mention topology. Is there any way to keep the existing features from being changed in this scenario?

Thanks,

John

[JohnSobetzer · Accepted solution]

Since no one has answered yet I'll pass on my interpretation of the tool.  Assuming the intent of the tool is to completely fill in the area between the line and the existing polygon, if it intersects the polygon at an edge where there is no existing vertice, it will add one to the existing polygon edge at the intersection point.  Otherwise it would either create a small gap or overlap, so small as to not be reflected in any area value.  The same thing would happen if you used the auto complete tool.

If you instead created the polygon using the create features tool, then you would not add a vertice to the existing polygon. You would have a topology error, that would be fixed on validation by adding a vertice.

[JohnHansen]

OK Johns,

That explanation makes alot of sense, and seems to describe how and why I am seeing the results I am. Thanks!

John