Sanborn Fire Insurance Map, detail; 1951. 

Sanborn maps give very specific details about each building, including construction materials. Yellow buildings represent frame construction buildings, blue represents concrete, and pink are brick buildings.  Sanborn maps also include details about the thickness of the walls, locations of doors and windows, the type of business, waterlines, and the type of sprinkler system.  Note the areas used for electrotyping, lithographing, label printing, paper baling, cutting and warehousing.

Published by Sanborn Map Company, New York, 1951.
Lithograph
History San José Collection