ST_SimplifyPreserveTopology

Introduction: Simplifies a geometry and ensures that the result is a valid geometry having the same dimension and number of components as the input, and with the components having the same topological relationship.

Format: ST_SimplifyPreserveTopology (A:geometry, distanceTolerance: Double)

SELECT ST_SimplifyPreserveTopology(polygondf.countyshape, 10.0)
FROM polygondf