The distinction
A market with no store of yours in it may still be fully covered by a store twenty minutes away in the next town. Conversely, a market you already operate in may contain population your existing catchment does not reach.
Whitespace is population outside the union of your routed catchments, filtered to places that resemble the trade areas where you already perform.
How to rank it
- Compute the union of existing catchments at your underwriting drive time.
- Find populated cells outside it that clear a minimum population floor.
- Score each on similarity to your best-performing existing trade areas.
- Subtract anywhere a competitor's catchment already dominates, unless you are deliberately going head to head.
Narrative Geo does not sample. Every trade area is routed on the actual road network with OSRM, against full Census/ACS population and a maintained POI set. The drive-time matrix is precomputed at 1.08 billion rows, so a national query across a 20,000-store chain returns in seconds rather than being metered per location.