Data sources
Combined Statistical Areas (CSAs) are built from Core Based Statistical Area (CBSA) boundaries using information provided in OMB Bulletins.
Boundary layer
The regions in the CSA boundary layer each represent a group of adjacent CBSA boundaries. The file name of the boundary layer extending into coastal waters is csa_b. The file name of the boundary layer with coastal shoreline boundaries is csa_j.
Inventory layer
The inventory layer contains point representations of each CSA entity. Each centroid in this layer is the balance point of the corresponding polygon, calculated based on the coordinate extremes of the polygon, so that the centroid falls within the largest polygon of the feature. There is only one centroid per feature.
The file name of inventory layer aligned with the csa_b layer is csa_i. The file name of the boundary layer aligned with the csa_j layer is csa_m.