Drive Time Map (Isochrone Calculator)
Create approximate travel-time rings for driving, cycling, or walking from average speeds. Explore 15- to 60-minute areas on a map.
The Drive Time Map creates approximate travel-time rings around an address or coordinates. It multiplies each selected duration by a representative average speed for driving, cycling, or walking. The exported GeoJSON is useful for early planning, but the rings do not follow roads or account for traffic, barriers, bridges, or turn restrictions.
These bands are planning estimates calculated from average travel speeds. They do not follow roads, traffic, barriers, or turn restrictions and must not be used for dispatch, navigation, or safety decisions.
Travel Time Bands
Drive Time Map Technical Specifications & Standards
WGS84 geodesic geometry
Standard global ellipsoidal coordinate reference system
Average-Speed Geodesics
Broad planning estimate; not road-level routing
GeoJSON · KML · CSV · SVG
Compatible with QGIS, ArcGIS, Google Earth & CAD
100% Client-Side
Calculations run in-browser. Zero coordinate logging.
How to Use the Drive Time Map (Isochrone Calculator)
Follow this step-by-step procedure to execute precise spatial measurements and export results.
- 1Set starting location: Search a street address, landmark, city, or click anywhere directly on the interactive map.
- 2Select travel mode: Choose between Driving (passenger car), Cycling (bicycle), or Walking (pedestrian paths).
- 3Choose travel time intervals: Select 15, 30, 45, or 60-minute travel time bands to visualize concentric commute rings.
- 4Inspect reachable land area: Review the total square miles and acreage enclosed within each travel time zone.
- 5Export isochrone boundaries: Click "Export Data" to download the travel polygons as GeoJSON or KML for GIS spatial analysis.
Geodesic Precision vs. Competitor Mapping Approaches
Most legacy mapping utilities (such as CalcMaps and FreeMapTools) rely on planar Web Mercator projections or spherical approximations, causing significant mathematical distortion at higher latitudes. GeoMap Suite computes exact ellipsoidal geodesics on the WGS84 reference ellipsoid.
| Calculation Model | Mathematical Basis | Distortion on WGS84 | Standard Tools | Practical Application |
|---|---|---|---|---|
| Planar (Web Mercator) | Cartesian dx² + dy² | 10% to 200%+ error | CalcMaps / Simple map tools | Distorts drastically away from equator. Inaccurate for true distance. |
| Spherical Great-Circle | Haversine (R = 6,371 km) | Up to 0.5% (~5 km/1,000 km) | Basic Google Maps wrappers | Ignores Earth's polar flattening. Reasonable for rough estimates. |
| GeoMap Suite Ellipsoidal | Karney Direct/Inverse WGS84 | < 15 nanometers (<0.0001%) | GeoMap Suite | Geodetic surveying, maritime, flight paths & legal boundary analysis. |
Worked Example 1: 30-Minute Commute Zone in Austin, TX
A homebuyer creates a preliminary 30-minute planning ring around Downtown Austin before checking candidate routes in a navigation service.
Input Parameters
- Origin
- Downtown Austin, TX (30.2672° N, 97.7431° W)
- Travel Mode
- Driving (Car)
- Duration Band
- 30 Minutes
Computed Outputs
- Isochrone Time
- 30 Minutes Driving
- Result Type
- Approximate geodesic planning ring
- Road and Traffic Detail
- Not included
Step-by-Step Mathematical Process
- Apply the tool's representative driving speed to the 30-minute duration.
- Convert the estimated travel distance into a geodesic ring around the origin.
- Inspect the ring as a broad screening area, then verify real routes separately.
Worked Example 2: 15-Minute Urban Delivery Zone for a Distribution Hub
A courier logistics service defines its guaranteed 15-minute express delivery perimeter in central Chicago.
Input Parameters
- Hub Location
- West Loop, Chicago, IL
- Travel Mode
- Urban Driving / Courier
- Time Window
- 15 Minutes
Computed Outputs
- Delivery Window
- 15 Minutes
- Serviceable Area
- Preliminary estimate only
- River Crossing Bottlenecks
- Not modeled
Step-by-Step Mathematical Process
- Select driving mode and a 15-minute band.
- Generate an average-speed geodesic planning ring.
- Check actual streets, traffic, access rules, and delivery feasibility in a routing product.
Understanding Your Results & Practical Interpretation
Distance Radius Circle vs. Road Isochrone Polygon
This tool converts time and a representative speed into an approximate distance ring. A true road-network isochrone requires a routing engine and can be irregular because it accounts for streets, barriers, and turn restrictions; this free static tool does not model those details.
Why the Real Reachable Area May Differ
Actual travel varies with road class, congestion, intersections, access restrictions, terrain, and barriers. Verify important trips with a current navigation or routing service.
Practical Applications & Real-World Use Cases
Real Estate Home Search & Commute Planning
Search for homes within an acceptable 20, 30, or 45-minute driving commute of your workplace or children's school.
Commercial Retail Catchment & Site Selection
Analyze potential customer density and demographics within a 15-minute drive of a prospective retail or restaurant location.
Non-Critical Early Planning
Create a rough visual screening area before using an authoritative routing, traffic, or dispatch system. Never use these estimates for emergency response.
Mobile Service & Delivery Dispatch
Establish fair delivery fee tiers and technician dispatch boundaries based on travel time rather than straight miles.
Mathematical Methodology & Geodetic Accuracy
Average-Speed Travel-Distance Estimate
Multiplies time by a representative mode speed, then draws a WGS84 geodesic ring around the selected origin.
Estimated distance = average mode speed × travel timeLimitations & Boundary Conditions
- •The rings do not follow roads or include traffic, barriers, bridges, turns, terrain, or access restrictions.
- •Use a current routing service before making travel, dispatch, safety, property, or service-area decisions.
Authoritative Reference Standards
Troubleshooting & Geographic Edge Cases
Why does the drive time polygon look irregular or jagged?
This tool draws smooth geodesic estimate rings. It does not follow roads or create cutouts for rivers, bays, mountains, or limited bridge crossings.
Can I generate isochrones for walking and bicycling?
Yes. Toggle the "Mode" selector between Car, Bicycle, and Walking. Walking isochrones use an average pedestrian speed of 3 mph (4.8 km/h), while cycling uses 10–12 mph (16–19 km/h).
Frequently Asked Questions
A true isochrone represents locations reachable within a specified travel time. GeoMap Suite provides an approximate average-speed planning ring, not a road-network routing isochrone.