Notes on QC Tools

August 6, 1999

These tools are useful for correcting some topological problems that Arcview out of the box
allows you to create (such as overlapping polygons and multipart polygons).  It also looks
for slivers (very small polygons) and void polygons.  You may want these things in your data
or you may be an old time Arc/Info user disturbed at the absence of what we all used to think
of as Topology.

There is a routine that selects a "random" sample of polygons so that you can check your attribute
editing and line work.  I'm not a statistician and borrowed the algorithm for calculating the
sample size.  If it's wrong let me know and I'll fix it.  I gave up trying to peruse the literature
for an equation that I could understand.

Jim Heald
healdj@fas.usda.gov

I have also made changes to the Arcview polygon draw tool in another extension that check for 
whether you are creating overlapping polygons (haven't been able to work out how to "fix" the vertex
editor unfortunately), but much of this code has been customized for our particular application so
would require some work to generalize.