The roman numerals indicate how many stories each building is and each color represents the type of structure. Yellow is wood, grey is concrete, blue is iron and pink is brick. The X's through the buildings indicate it is a garage. Brown indicates stone structures. A square with an X indicates elevators.
I am selling my collection of rare maps. If there is an area or street address of Brooklyn, Manhattan, Queens, Staten Island, Bronx, Long Island, Rochester, Buffalo, Elmira, Newark, Atlantic City, Essex County, Montgomery County, Bergen County, Cleveland, Toledo, Washington, D.C., Toronto, Montreal, Vancouver, Portland, Maine, Denver, Boston, South Boston, Dorchester, Roxbury, Everett, Worcester, Brookline, Quincy, Malden, Lawrence, Middlesex County, Philadelphia, Pittsburgh, Harrisburg, Wilkes-Barre, Reading, Berks County, Delaware County, Montgomery County and other cities that you might be interested in, contact me. I have insurance maps from 1880 to mid-1950s. Looks great framed! Check out my other items!