Shades of Tufte and The Visual Display of Quantitative Information. The outstanding change between 1932 and 1933 was the discarding of the irrelevant exact layout of the lines, and using instead the simplest possible topological layout. By no longer showing the physical distances between stations, or the exact weaving in and out of the lines, Harry Beck's layout is the basis of most modern underground railway maps.
For the time it was an astonishing leap of representation, regarded with great suspicion.
As much as I love the qualities of the new map, the old one DOES convey useful extra information, especially now we've become sufficiently acquainted with the modern one. I would like to see an updated old-style map, it would be a nice (retrograde) evolution.
The "SnapMap" of London shows the actual routes of the lines and the locations of the stations on a simplistic, but accurate enough, map of London. I use mine all the time.
For the time it was an astonishing leap of representation, regarded with great suspicion.
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