The web Atlas of Barcelona is an interesting example of how take a catalogue thought to be in only in paper to digital world. 

Specifically, the work is the collection of old cartographic engravings of the city of Barcelona, made and edited by Ramon Soley and distributed by Editorial Mediterrània in two volumes in 1998:

Soley, Ramon (1998): Atles de Barcelona, 2 vol. Barcelona, Editorial Mediterrània

The web edition is very complex, has a nice design, neat, and takes advantage from potential of media.  es muy completa, tiene un diseño agradable, bien cuidado, y aprovecha el potencial del medium. The maps can be reached through three different index: numeric, onomastic and typological. Also, it is offered an estructure of twelve series of maps that allow illustrate historical moments seen by the city and reflected in the engravings, as well as representations or elements characteristics of the city.  

Moreover, the authors of the web are open, and invite to add external contributions that allow the improvement and complexion of the cartographic representation impressed of Barcelona until 1900.