Convert from em to city block [South, West U.S.]

Unit Definition (em)
The em is a printer's unit of relative distance. One em is the height of the type size (in points) being used. If 12 point type is being set, then one em is 12 points, and so on.

Unit Definition (city block [South, West U.S.])
The south west city block is an informal unit of distance popular in the U.S. A block is the average distance between street intersections in the rectangular street grids common in most American cities. The length of a block varies from about 1/20 mile (80 meters) in New York to about 1/16 mile (100 meters) in many midwestern cities to about 1/10 mile (160 meters) in cities of the South and West. (In New York and some other cities, streets running on one direction are closer together than streets running perpendicular. In these cities, people often speak of "short blocks" or "long blocks.")