We obtain footage of sidewalks around the city, along with the location of each piece of footage that we find, and when the footage was taken. We could get this from buying CCTV footage from business owners, or stationing cameras at various places in the city. Finally, we can take footage from on top of apartment complexes, or from low flying drones.
We count the number of pedestrians in the footage using image recognition. With this data, we can calculate the pedestrian flow in different parts of the city at different times.
We sell this information to corporations, they will want the information when deciding where to lease property. I know for a fact that this information is in demand.
I am completely comfortable working on the technical side of things, but I need help from someone with marketing experience.