As I write these words, Frederick Wiseman’s 30th film, Public Housing, is about to be broadcast, Dec. 1 , through PBS, the national network that has presented all of his documentaries. It concerns the Ida B. Wells housing development on Chicago’s South Side. The sites of his past documentaries have varied from high schools to hospitals, from public parks to private playgrounds. He has shown us the inside of military and police units, welfare and model agencies, prisons, a primate research lab, a meat packing plant and a zoo.