How do you make a compelling documentary about land use and gentrification? Fill the big screen with some of the most thrilling action shots and masterfully edited montages of roller skating. In “United Skates,” filmmakers Dyana Winkler and Tina Brown explore how discrimination, racist zoning policies, gentrifying land grabs and a shifting real estate market have threatened roller rinks among black communities and a vibrant, decades-old roller skating culture.

Those shots put the camera and the audience right in the middle of the rink, but the film’s real achievement is the cross-country storytelling that links the fates of three families — in California, Chicago and North Carolina — to a tradition as vital as any other.

The filmmakers capture countless regional skate styles showcasing elaborate footwork and ballet-esque spins, along with the music that propels their bodies. Chicago’s Buddy Love, among a handful of black roller rink owners, hosts a Chicago-only skate style soundtracked by cut-up James Brown songs, resulting in joyous explosions across the screen.

Reggie Brown in North Carolina drives several hours to make his pitch for a rink to host a monthly “adult night." Rinks have used that label — along with "soul night" and other racially coded terms — to isolate and discriminate against black skaters, but for Brown it at least holds the promise of keeping the culture alive.

And there’s Phelicia Wright’s family of five, all skaters, who have seen the rise and near-fall of Los Angeles skate culture, from Skateland in Compton and World on Wheels in Mid-City to their pivotal role as hip-hop venues and as turf for the rival gangs that called each spot their own. Rapper Coolio, among the many hip-hop icons interviewed throughout the film, explains that while the parking lots were the gangs’ territory, the neutral zones inside remained hallowed grounds, and communities ensured their survival. Two decades later, the fight is still worth having to protect those spaces and the dignity of the riders who light them up.