An urban planner, Keast is also the co-founder of The Laneway Project, a local effort aimed at looking at ways to improve the city's laneways.
"We see all these laneways in Toronto as a hidden layer of public space, this resource that we haven't really utilized in a very effective way," he said Wednesday in an interview on CBC Radio's Metro Morning.
"A lot of people don't know actually how extensive the Toronto laneway network is," said Keast.
Laneways are increasingly seen as viable locations for new housing as the city continues to grow and real estate prices skyrocket.
In addition to mapping, the project is aimed at improving laneways to the point where they become destinations. The movement was inspired in part by Melbourne, Australia, where little-used laneways were transformed into vibrant public spaces.
The group hopes to try bringing pop-up shops, public art and venues for community events to Toronto laneways.
Their website points to successful laneway revivals in Seattle, Perth, Australia, and Chicago.
Project Laneways will also host an evening summit on Thursday, Nov. 20, to discuss potential laneway revivals. The summit will be moderated by CBC Radio One reporter and producer Mary Wiens.
Keast said he hopes revitalizing laneways will become a "big movement" in Toronto and a way to relieve pressure the city's growth has put on the city's public spaces.
"There are a lot of people who've been working on laneways behind the scenes for a long time. We're trying to bring those voices together under one umbrella and push it forward."