Enid Haupt Garden. (OLIN/ASLA)

Glenn LaRue Smith may be one of the few District residents who loves to use Metro’s problem-plagued escalators, specifically the north exit escalator at the U Street Metro Station.

As you move upward, you see the African American Civil War Memorial reveal itself in all its drama. “I never realized it was such a powerful structure until I came out of the Metro station,” said Smith, a landscape architect with Smith-Murray Studios in Northwest Washington.

Smith is one of 20 landscape architects who have helped create a new online guide to the city’s important outdoor spaces, some world famous, others, such as the Civil War memorial at U and Vermont Avenue NW, not as well known. The Web site, The Landscape Architect’s Guide to Washington, D.C., was launched Sept. 13 by the American Society of Landscape Architects, and there is a version for mobile devices.

Smith and his fellow guides bring the site user more than 75 designed spaces, explained through the eyes of a design professional. The subjects include monuments, gardens, museum exteriors, parks, plazas — a tapestry of the city’s civic landscape.

One of the quirkiest? The narrow, steep stone steps in Georgetown that figured in the 1973 horror flick “The Exorcist.” Interesting fact? The Washington Monument is located a distance from its originally proposed site, which wouldn’t have supported its weight.

African American Civil War Memorial photos. (Glenn LaRue Smith/ASLA)

The guide is divided into 16 discrete tours in all quadrants of the District and a portion of Arlington County. It includes a map that can be printed out for walking or cycling.

The guide is the first of its kind in the United States and provides a template for similar Web-based tours that will be developed in other cities, according to the society.

It is aimed at Washington’s 19 million annual tourists but will be of use to residents as well, providing “a fresh perspective on both iconic and brand new landscapes within the nation’s capital,” said Nancy Somerville, the society’s chief executive.

Somerville and others acknowledge an additional motivation for the guide: to elevate public understanding of what landscape architects actually do.

“I think it will go a long way to show we are designers of human spaces that people can enjoy,” said Smith. In addition to the African American Civil War Memorial, his tour examines Meridian Hill Park, Union Row and the Howard University Quadrangle.

As with architects and engineers, much of the profession’s work is not apparent and deals with concerns such as circulation patterns and storm-water management and has focused increasingly in recent years on sustainable design.

But the guide should also open eyes to the aesthetics of a design, from the style of a drain grate to the fact the World War II Memorial includes a facsimile of the ubiqui­tous GI graffiti “Kilroy was here,” said Susan Spain, a landscape architect with the National Park Service. “The more you look at things, the more you know about the story and the more you value it,” she said.

Somerville said the guide will convey that Washington’s familiar landmarks were “not something that magically appeared but evolved over a long period of time.”