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Strangeness - gaps unintentionally created while editing

Question asked by cdspatial Champion on Oct 13, 2015
Latest reply on Oct 15, 2015 by cdspatial

I've been asked to update our City's parcel layer based on changes the County sent us and am noticing gaps being created when editing.  This happens both when editing in a Version of the Parcels in SDE and when editing the same data in a File Geodatabase.  We are using ArcGIS 10.2.1. with an Advanced License.


For example, one of the updates was a parcel split.  Using the County's line layer, I set out to split the parcel.  Red lines are the County data and the Green polygons with black borders are the City parcels data.  So in this case, the first task is to split into two the left-side polygon to create "Polygon A" and "Polygon B" (currently A and B are one parcel).


NOTE - our data varies from the County's slightly (long story) and that is currently OK, so the task is to modify our data as close as possible based on the County's changes.  So we are going to split the parcels (yellow highlighter) but not worry about the fact the county data for the boundary of "A/B" to "Polygon C" is off by 0.0000796 feet.




When I do the split, weirdness results.  The original polygon has now been split to "Polygon A" and "Polygon B", but now there is a gap between those two and "Polygon C" (the white space).  That was an unexpected outcome.


To do the split, I used the "Cut Polygons Tool" on the Editing Toolbar along with the "Trace", and then spanned the gap well into "Polygon C" with the "Cut".  So how come there is a gap there now (the white space)?




The gap is definitely a problem.  As part of testing to see what is going on, I tried going one step further and Merging the polygons that I had originally split.  The result is they do merge but the gap remains.  So it seems unlikely to be a visual thing.




So I'm a bit puzzled.  I've done a considerable amount of editing over the past several years but not run into issues like this.


Note that the scale depicted here is very zoomed in (1:0.02).  Given that this is happening at this micro level, I almost wonder if the XY Tolerance and Resolution settings are off.  Here is what we are using (set same for both the File Geodatabase and SDE Version).







So I guess my question is what is causing this and how do I fix it.  I know this can be corrected "after-the-fact" with Topology, but we'd prefer not to create problems on the front end while editing.  It almost seems like a setting is off.  Any ideas?



Chris Donohue, GISP