"There is no branch of detective science that is so important and so much neglected as the art of tracing footsteps," Holmes remarked in A Study in Scarlet
In this case, the the art is being taken to a science and the world's police - forces in 128 countries, to be exact - are teaming up to develop a comprehensive database of footprints.
Foster + Freeman, a forensic science company has developed a proprietary software called SICAR that essentially is a version of Sherlock Holmes's brain on steroids. The software studies the patterns, treads and shapes on shoe soles and adds them to the database of over 15,000 prints. When an image is searched, the process of scanning the database for a match takes only 1-2 minutes.
It's still amazing to think that Holmes to retain so much of this in his own brain without the aid of a computer - 140 varieties of cigar ash, 42 different impressions of bicycle tires, etc. While 15,000 prints would be impossible for any human to remember, it's encouraging to know that Holmes was the original crime computer and the inspiration for much more today.