A new way to see 'city by the bay'

The cable cars won't be defying gravity on San Francisco's hills for the next two years. The whole system is down for renovation. But there's a new way to see the city - at least for the next two months - that might well provide some enduring memories.

An exhibition that opened Oct. 28 at the San Francisco Museum of Modern Art enables visitors to ''see'' the city through the works, great and small, of hundreds of architects. The San Francisco chapter of the American Institute of Architects (AIA) has collaborated with the museum to mount a presentation that conveys, within a few square feet, a sense of the city that miles of sightseeing cannot match.

Each of four themes is given focus by an amazingly accurate wooden model - three of San Francisco landmarks, and the other of two distinctive types of buildings. Each theme is expanded through large photo reproductions of scenes and structures, mounted in curved colonnades and niches along the museum's fourth-floor gallery walls.

Theme One, ''Civic Pride,'' features an intricate model of San Francisco's famous City Hall dome. Pictured on the facing colonnade wall are architectural manifestations of civic, corporate, and institutional pride: the Pacific Gas & Electric Company building in the financial district and the 1924 Palace of the Legion of Honor, a museum and World War I memorial modeled after its namesake in Paris.

Theme Two, ''Utility,'' is marked by a model of the Golden Gate Bridge pylon that supports the span on the San Francisco side. It is so faithful in intricate detail that the viewer can learn more about the structure of the famous bridge in the museum than could ever be discerned at the site.

Theme Three is ''Home and Work.'' Its wooden model portrays, on one face, the front of a Victorian residence of the 1870s and, on the other, the Hallidie Building, built in 1917 in the financial district and said to be the first office building in the world featuring ''glass curtain'' outer walls.

For Theme Four, ''Pleasure,'' the mood is set by a model of Golden Gate Park, where bare, wind-swept dunes were transformed into a huge green playground that stretches from the Pacific shore into the heart of the city.

AIA member Marc Goldstein, a co-curator of the exhibition, described the dual purpose of the show: It tells the story of San Francisco in a way that is meaningful to the youngest and most unsophisticated visitor as well as to the older and more knowledgeable. No less important, he says, is that ''the visitor will walk out of the exhibition with a new understanding of what an architect is.''

The chief shortcoming of the exhibition: It will close Jan. 2, 1983.