Three things is a mapbox GL powered prototype that takes in geoJSON data and maps it on a map for you. In addition, it converts KML or shape files often used by city planning departments to publish open source data into geoJSON to make any of those public use resources easily mappable without access to expensive GIS software.
The example in the prototype overlays city zoning data and traffic speed studies on top of strava run data from commuters and live data gathered from custom made sensors placed in target areas. When seeing all of this data in one place, city planners or citizens could make verifiable claims to city problems. Can I prove that an intersection without a crosswalk installed is very dangerous if I have foot traffic and commuter biking data along with car counts of that intersection? Can we start to re-value property based on how noisy the construction nearby is? Three things allows you to visualize spatial data to get a more accurate view of an area.