Mapping the Nation: Creating the World We Want to See

145 Smart Planning Detroit has some of the most visible signs of transformation. A large open lot in central downtown—the result of the 1998 teardown of the flagship Hudson’s department store—is being filled by what will be the city’s second-largest building, set to contain a dynamic mix of event space, stores, restaurants, hotel rooms, offices, and residences. Evidence of the rich mix of the area’s assets and revitalization are now available for anyone to see in 3D maps showing not only the city’s present but also the entire region’s future. Development plans for the next 30 years in Detroit and a couple hundred surrounding communities are now clearly visible, thanks to what’s being recorded in the GIS used by planners and municipal leaders in southeast Michigan. “We wanted to show the potential of a site, even if all we had was a city mayor saying, ‘We’re going to get this developed, and it’s going to have a hotel, restaurants, and condos.’ We needed something we could see and share, beyond just our imagination,” said Jeff Nutting, forecast coordinator for SEMCOG. Seeing the Long-Range Future Using GIS to compile details and conduct analysis every five years, Nutting oversees SEMCOG’s 30-year forecast of population, housing, employment, and land-use changes. The forecast supports spending decisions on infrastructure management—such as water, sewer, and transportation projects—including what roads and bridges to widen or repave. For the agency’s 2050 forecast, SEMCOG asked 232 communities in the region for their development plans in fine detail. Instead of simply asking how many units were planned for a specific parcel, SEMCOG captured site and concept plans that show how roads and buildings are laid out, how tall the buildings will be, and how much square footage they will have. The site plans also convey the amount of pavement planned, which informs impervious-surface calculations for stormwater planning. “We thought, if we used planning documents, it would be something they already have and we would be speaking their language,” Nutting said. More than 200 communities contributed plans and data in the 2022 round, compared with fewer than 100 in 2016. Most planners in the region are so busy managing developments, they don’t have time to calculate growth. SEMCOG envisioned a new kind of outcome. By inputting plans, the forecasting team would provide a detailed and realistic model to visualize what was coming. If the planner didn’t have a site plan for a planned development, Nutting and his team used ArcGIS Urban to design a concept plan for the site. The planner was presented with some option of development type, and then a rulesbased model showed what that would look like. SEMCOG processed 800 development site plans as part of the forecast process creating a digital twin of the region. Rather than points on a map, the new map shows what kind of growth is planned, including the building footprints of all multifamily housing projects or single-family homes, and gives planners an awareness of regional development patterns. “It’s much easier for communities to double-check what we’ve put together,” Nutting said. “We’re giving them a map of current and future buildings.” Watching the Detroit Region Expand Putting all the data on a map helps SEMCOG see what things look like regionally and triggers questions about where development will go next. One of the things that the forecasters have seen are fewer planned storefronts and office buildings.

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