We had a request for a clearer version of the image we discussed in our post last year, which shows changes in the catalogued subject of Library of Congress books over the course of several hundred years. Jon Orwant from Google was kind enough to send an updated image, which we’re sharing here. I include below his description of the visualization.
“The visualization…was derived exclusively from the metadata feed of the Library of Congress. The LoC catalog doesn’t restrict itself to American or even English language books, but likely does have some sample bias (as every union catalog does).”