Service Coverage Gap Viewer
Place multiple centres and radii to see where coverage overlaps or leaves gaps.
By Aryan Khan, Founder & Editor · Updated October 2026
For example, two depots 10 miles apart with 10-mile radii overlap by 39.1% of each circle — the viewer turns that statistic into a map you can argue with.
How to use Service Coverage Gap Viewer
One circle always looks fine. Two start telling the truth:
The Service Coverage Gap Viewer lets you place multiple centres and radii and see where coverage overlaps or leaves gaps. Add your depots, hubs or towers and read the map: doubly served ground, singly served ground, and the holes nobody is serving at all.
- 1Add service points and radii.
- 2Look for uncovered pockets.
What people use Service Coverage Gap Viewer for
1. Depot and branch networks
Overlapping delivery circles double-serve the same streets while a gap starves others. The viewer is the network review's first slide — single rings start on the Service Area Map.
2. Tower and transmitter planning
Signal coverage has the same geometry: overlap for handover, gaps for dead zones. The map speaks both languages.
3. Franchise territory audits
Granted territories that overlap breed disputes; gaps are unclaimed market. Both print clearly here.
4. Emergency coverage reviews
Stations' response rings over a county: the gap is where the next station belongs — an argument this map makes better than a spreadsheet.
Worked examples
Two 10-mile circles: centres 5 mi apart overlap 68.5% of each circle; at 10 mi apart, 39.1%; at 14 mi, 18.8%; at 17 mi, 6.8%; at 20 mi they only touch. Spacing decisions live on this curve.
Three circles in a triangle can each overlap their neighbours and still leave a curvy triangular hole in the middle — the classic gap this viewer exists to expose.
Overlap of two equal circles
Radius 10, overlap as a share of one circle — computed from the lens formula.
| Centre distance | Overlap area | Share of each circle |
|---|---|---|
| 5 mi | 215.2 sq mi | 68.5% |
| 10 mi | 122.8 sq mi | 39.1% |
| 14 mi | 59.1 sq mi | 18.8% |
| 17 mi | 21.4 sq mi | 6.8% |
| 20 mi | 0 | Touching only |
Overlap is not waste by definition — services want some (handover, choice, resilience). The viewer shows the amount; your operation decides how much is design and how much is accident.
How to interpret the result
The most common errors come from using a correct result to answer the wrong geographic question. Keep these points in mind for Service Coverage Gap Viewer:
- Verify areas against a known object first — measure a football pitch or a city block you know — and you'll calibrate your eye for what a hectare or acre looks like at your zoom. The map preview is the unit your intuition trusts.
- When exporting polygons for reports, store the radius and unit in the feature properties (the exports here do). Future-you, reopening the file in a GIS, will otherwise have to re-derive what the circle meant.
Limits & appropriate use
Circles and polygons are geometric truths with semantic limits. A radius says nothing about rivers, one-way systems or response times; an area says nothing about what is inside it. The most expensive misuse is treating a geometric catchment as a service promise — which is why the isochrone tools exist as the temporal counterpart, and why the pages cross-link the two insistently. A second limit is resolution: drawn vertices capture the boundary you click, so curved shores want more clicks, and the perimeter grows (correctly) as you add them — the coastline paradox, politely present in every honest measurement tool.
Within geometry, the numbers are exact on the sphere: areas by spherical excess, boundaries by destination math, exports with their parameters embedded. The escalation ladder is short: cadastral precision needs licensed surveys; population-inside-shapes needs census blocks; drive-time promises need the routing engine. Used as the fast, auditable, shareable geometric layer that feeds those heavier instruments, this is exactly the right tool — and it says so.
- Cadastral/legal area → licensed survey with local datum practice.
- Population inside shapes → census blocks, not city-point sums.
- Response-time promises → isochrones plus operational buffers.
Data & methodology
The workspace draws multiple spherical circles for visual comparison; it does not calculate uncovered areas or guarantee real service coverage.
For source details, licences and model limitations, see Data Sources and Methodology.
Key terms worth knowing
- Catchment
- The area or population served from a centre, geometric or temporal.
- Perimeter
- The summed great-circle length of a drawn boundary.
Editorial guidance: MapBench explains the method and limitations so the tool can be used as a transparent reference, not as a black-box answer. For legal boundaries, safety-critical routing, surveying, engineering, regulated decisions or official statistics, verify the result with the responsible authority or a qualified professional.
Category: Radius & Area. Results are intended for everyday analysis and planning unless a page explicitly states otherwise.
Method, assumptions & limits
- This tool’s method
- The workspace draws multiple spherical circles for visual comparison; it does not calculate uncovered areas or guarantee real service coverage.
- Before relying on the answer
- Check the centre, radius or drawn vertices and the selected units. A geometric footprint does not describe which roads or entrances are accessible.
- What the result cannot establish
- A radius is not a travel-time guarantee. For parcel boundaries or legal land area, use an authoritative survey.
Coverage: Worldwide. Search, basemap and external data requests may use third-party services; browser-based does not mean every operation is offline. Read the source and licence notes, calculation methodology and privacy policy. If a result looks inconsistent, report a correction with the inputs and mode used.
Frequently asked questions
Clear answers about the calculation, accuracy and appropriate use.
Optimal placement?
This visualises gaps — site selection still needs demand data.
Is a radius the same as driving distance?
No. A radius is a geometric circle around a centre point. Driving reach depends on the road network and usually has an irregular shape.
Can I use this for service-area planning?
Yes for first-pass planning. Use a drive-time or road-network tool when accessibility matters more than straight-line coverage.
Are map measurements legal survey measurements?
No. MapBench measurements are planning/reference outputs unless a page explicitly states otherwise. Use a licensed surveyor for legal boundaries.
What counts as a gap?
Any ground inside your region of interest covered by no circle. The viewer makes gaps visible; whether a gap matters depends on who lives or travels there.
Unequal radii?
Centres carry their own radii — a flagship's 15-mile ring and a kiosk's 3-mile ring analyse together fine.
How many centres can I place?
Enough for a real network review; beyond a dozen or so, a GIS earns its licence. This viewer owns the planning conversation's scale.
Overlap percentage of what?
Shares here are quoted per circle. Union coverage (total ground served at least once) is the companion figure the map shows visually.
Roads change everything, no?
Real reach follows roads — the drive-time refinement comes after the geometry review, which catches the structural mistakes roads cannot fix.
Where should a new centre go?
In the largest gap's heart, tested by placing it and re-reading the map — the iterate-here loop is the planning method.
Population-weighted gaps?
This viewer is geometric. Overlaying population is the Buffer & Overlay Analyzer's counting job next door.
Can I save the layout?
Centres and radii are the layout — note them and the map rebuilds exactly.
Related tools and resources
Single areas: the Service Area Map; counting inside: the Spatial Buffer & Overlay Analyzer; hubs: the Sales Territory Radius Planner.
More free tools
Sources, methodology & editorial trust
- ✓ Browser-first processing where supported
- ✓ External sources are documented
- ✓ No account required for public tools
- ✓ Review data sources
Calculations are documented with their assumptions, limitations and source context rather than presented as unexplained answers.
Reviewed and maintained by Aryan Khan, Founder & Editor of MapBench.
Part of our radius & service area hub
Service Coverage Gap Viewer sits in the radius & service area cluster, alongside 18 other tools that answer neighbouring questions with different methods or datasets.
You may also need
When this answer is only part of the job, these clusters cover the next step.
Read the guide behind this tool
How to Draw a Radius on Google Maps — Google Maps has no radius button. Here are the exact workarounds to draw a radius circle — plus free tools that do it in one click.