Description: This data set provides eight feature classes. The base feature class is called esri_pl and isn't generalized. The weighted centroids feature class is called esri_pl_cent. The centroids are weighted by the U.S. Block Centroids population distribution. Use the weighted centroids in report aggregation and spatial overlay operations. The esri_pl and esri_pl_cent feature classes contain all the attributes. There are six generalized boundaries feature classes and called: esri_pl_gen2, esri_pl_gen3, esri_pl_gen4, esri_pl_gen5, esri_pl_gen6 and esri_pl_gen7. Use the generalized boundaries when creating study areas.