An ancient map of Rome that's surprisingly up to date

In 1748, architect and surveyor Giambattista Nolli completed a map of his hometown. The Pianta Grande di Roma ("Great Plan of Rome") was built from 12 minutely detailed copper plates, covered six by seven feet in its assembled state, and was so accurate that it continued to be used as the basis for government maps of the city until the 1970s. In 2005, a team at the University of Oregon brought the map online in order to "create and implement an innovative and highly interactive website and teaching tool for the study of the city of Rome." It may be a wordy mission statement, but the University of Oregon team certainly met its goals - The Interactive Nolli Map Website offers a good deal more than just a new look at an old map.

When created, the "Great Plan" was not only an impressive scientific and artistic achievement, it also set some cartographic precedents that are still followed today - such as Nolli's choice of the ichnographic, or plan, style of illustration rather than the more popular "bird's eye view." Nolli's was also the first map to use dark shades to mark buildings and private spaces and light shades for streets and public spaces, and the first such chart oriented so that North, rather than East, was at the top of the page. (In fact, the phrase, 'to orient' oneself, comes down from the earlier practice of placing the East at the top of maps.) Now, in its interactive incarnation, the map continues to set new precedents, as it folds history, cartography, urban design, and even architecture into a single presentation.

The layout of the Interactive Nolli Map Website is basic, though attractive enough, with a simple navigation bar at the top of each page and a handful of images below (which link to a collection of articles). Even the icon that launches the site's main attraction, the Nolli Map Engine, borders on the nondescript, but looks can be deceiving, and the application behind that link is an already impressive piece of Flash programming - with additional enhancements planned for the future.

Opening into a new window, the Map Engine presents the "Great Plan" in an interactive interface with an intriguing collection of options. Fairly standard features in the Map Engine include drag and zoom capability (with an impressive degree of magnification available), a navigational thumbnail image, one-click access to the last image viewed, and the ability to print and bookmark the current display. A less common feature (in fact, one I've never seen before) is an "Enhance this map view" button which, surprisingly, slightly blurs the image on display. While that may seem counterintuitive, the process actually does make the map easier on the eyes, by smoothing the jagged, pixellated lines of the map when viewed at extreme magnifications.

In addition to these basic functions, the Map Engine also employs nine informational layers that can be overlaid above the map - in any combination and at any magnification. Already activated on launch is a layer that adds color to the Tiber River over the black and white map. Other layers locate Gardens, Fountains, and Pathways in the city, trace the defensive Walls of Rome, and provide captions for the decorative imagery at the bottom of Nolli's opus. More layers are planned for the future, and will include such features as cafes, census data, archaeological sites, and even flood zones.

Once selected, each layer also offers a "Fade" control, which allows visitors to set the opacity of the optional information. The pin-like icons locating fountains are unobtrusive even at full opacity, but depictions of the various gardens completely block large areas of the underlying image. The fade control is most effective when used with a layer holding a satellite image of the city.

Provided by Space Imaging, Inc., this 1-meter resolution satellite layer nicely brings together the state of mapping technology of the present with that of the past, but it does more than simply serve as a symbolic meeting of eras. It also reveals that (a) the layout of the center of Rome has remained remarkably stable over the last 250 years, and (b) that Giambattista Nolli was a spectacularly accurate mapmaker. It's astounding to this layman that someone bound to Earth's surface could so precisely chart the streets and structures of the city, but shifting the opacity of the satellite layer to move to and from the Nolli Map demonstrates a stunning degree of correlation. Chances are that this simple act of comparing virtually identical 'before and after' images will occupy the majority of your visit here.

After enjoying the visual attractions of the Map Engine, surfers can also turn to a collection of articles which will add some context to the graphic component. Divided into four "Modules" (Natural Features, Architecture, Social Factors, and Cartography), this resource provides brief introductions to such subjects as the history of Rome's city walls, and its "disabitato" (the "uninhabited place" outside the city center). Short and written for the nonexpert, these articles are well worth the read - and will probably send most visitors straight back to the map. One such essay notes that the work's geographic accuracy was "unremarkable" for its time, but claims the surveyor's real achievement was in the unprecedented amount of detailed information he managed to record in the document - including the interior architecture of many buildings, and such minutiae as the locations of open and closed street drains.

Finally, if you feel the need to search for specific features or landmarks, or if you want to identify a numbered annotation on the map, a Gazetteer holds names, basic information, and direct links to the Map Engine for more than 1300 locations recorded by Nolli. A keyword search will return relevant results from the Map Engine and the rest of the site.

Giambattista Nolli died at the age of 55 less than 10 years after the completion of his masterpiece. One can only imagine what his reaction would be to today's satellite mapping techniques, or to the interactive, multilayered form his work has taken in his absence. For this present-day observer, the latter is an impressive achievement, offering entertainment value for the casual visitor, and enough deep content to make it a valuable learning resource. With the amount of traffic it's likely to attract, the "Nolli Map Website" had better be on a robust Web server.

The Interactive Nolli Map Website can be found at http://nolli.uoregon.edu/