20231213 16534800 1.0 TRUE Sinkhole Polygons This dataset is a polygon coverage of the sinhole boundaries as determined by using LiDAR data. The polygons relate to the point coverage using the KPolyID field in both coverages. If a point has a KPolyID, the KPolyID links to the same field in the sinkhole_polys coverage. If the KPolyID is empty the sinkhole is an historic sinkhole and does not show up in the LiDAR data. Calvin Wolter developed this coverage for the Iowa DNR