# How Do I Set XY Cluster Tolerance for Topology Rules to Meters Squared?

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04-27-2021 06:00 AM
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New Contributor II

Hello, I have a conceptual question regarding the XY Cluster Tolerance setting in Esri’s topology tools and this may be the place to check.

I am trying to establish a cluster tolerance of 8 square feet for new topology rules that check for voids and gaps within and between polygons, but the tool only allows me to set a cluster tolerance in meters. No problem, I can convert feet into meters easily, but I am confused as to why it doesn’t allow me to enter meters squared? Given that I am apply this rule to polygons, I know that the tolerance I want is 8 squared feet – not 8 feet - would I want to take the square root of 8 feet to get 8 ft2? That would equal (approx.) 2.828427 ft – when squared, this equals 8 squared feet.

Or is there something else going on behind the scene of the XY Cluster Tolerance setting that is obvious that I am missing? Any insight is appreciated.

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MVP Notable Contributor

The cluster tolerance refers to the linear distance along an axis, if you look at the topology docs.

If you want the encompassed "cluster area" to be 8 square feet, then yes, you would take the square root of that. I suspect they ask the user to specify the linear distance as that is easier to conceptualize, especially if you're working with squared decimals. I can imagine collapsing points within 0.001 feet of one another, but "0.000001 square feet" means a bit less to me without drawing it out.

To get another unit, that will depend on the units defined in the Feature Dataset within which the topology has been created. In one of our topologies, the dataset is in a State Plane CRS, so the cluster tolerance is in the CRS units, which is feet.

- Josh Carlson
Kendall County GIS
2 Replies
by
MVP Notable Contributor

The cluster tolerance refers to the linear distance along an axis, if you look at the topology docs.

If you want the encompassed "cluster area" to be 8 square feet, then yes, you would take the square root of that. I suspect they ask the user to specify the linear distance as that is easier to conceptualize, especially if you're working with squared decimals. I can imagine collapsing points within 0.001 feet of one another, but "0.000001 square feet" means a bit less to me without drawing it out.

To get another unit, that will depend on the units defined in the Feature Dataset within which the topology has been created. In one of our topologies, the dataset is in a State Plane CRS, so the cluster tolerance is in the CRS units, which is feet.

- Josh Carlson
Kendall County GIS
New Contributor II