Another community group, Detroit Declaration, has developed a land-use policy that proposes setting up urban farming and reducing the size of lots for building to encourage housing development known as in-fill.

Image Janet Jones, a bookstore owner, is cautious. “We have a lot of history of things being promised, land being taken,” she said. Credit... Fabrizio Costantini for The New York Times

Yet another proposal has come from Mr. Ogden’s group, Next Detroit Neighborhood Initiative, which calls for an intensive intervention to prop up the city’s strongest areas, the city’s tax base and community anchors, which are just starting to suffer after weathering decades of storms.

“It’s really about reorganizing our land to make a more livable city,” said Tom Goddeeris, an architect who lives in the vibrant northwest part of the city and is a longtime advocate of rethinking Detroit. “I don’t know that it’s ever been done before on our scale, but we’ve got to get started.”

Despite the energy poured into rethinking the city by a half dozen groups, there are limits to how much those outside government can accomplish. There are both political and financial obstacles to putting any of the plans into effect.

For instance, though many of the plans presented to the city for consideration aim to create density in viable neighborhoods by consolidating and relocating residents from dying or dead neighborhoods, most do not go so far as to say which areas they would choose for destruction. Those decisions, group leaders said, are for the city to make.

“What we believe is that it should be data driven, in collaboration with residents,” said Anita Lane, director of programs at Community Development Advocates of Detroit. Any process for redesigning the city, she said, “needs to have all the stakeholders coming together to take ownership for this.”