Read and Communicate a Location Using Coordinates
The short answer
GPS coordinates describe a point on Earth with two numbers: latitude (how far north or south of the equator) and longitude (how far east or west of the prime meridian). To communicate your location after a breakdown, read latitude first, then longitude, include the direction (north/south, east/west) or the minus sign, and read every digit individually. In the continental US, latitude is north (positive) and longitude is west (negative in decimal form).
One qualification changes how useful this is: coordinates are only as good as the format the listener expects and the accuracy of the device that produced them. Telling a dispatcher or tow operator which format you are reading, and pairing coordinates with road-based cues, reduces the chance of a misunderstanding.
Coordinate formats, with examples
The same point can be written in three common formats. The numbers below are an illustrative format example only, showing one location expressed three ways.
Decimal degrees (DD): 39.73920, -104.99030; Degrees, decimal minutes (DDM): 39° 44.352' N, 104° 59.418' W; Degrees, minutes, seconds (DMS): 39° 44' 21.1" N, 104° 59' 25.1" W
Format | How it looks | Where you commonly see it; Decimal degrees | Two decimal numbers; minus sign for south or west | Smartphone map apps, emergency and dispatch software; Degrees, decimal minutes | Degrees plus minutes with decimals, N/S/E/W letters | Some GPS units, marine and aviation use; Degrees, minutes, seconds | Degrees, minutes and seconds, N/S/E/W letters | Paper maps, some phone compass apps, surveying
Decimal degrees are usually the simplest to read aloud and to type into another device. If your screen shows a different format, read it as shown and say which format it is rather than converting it in your head under stress.
How precise the numbers need to be
One degree of latitude spans roughly 111 kilometers (about 69 miles). That means each decimal place matters:
Two decimal places (0.01°): roughly 1.1 km, enough only for a general area; Three decimal places (0.001°): roughly 110 m, about a city block; Four decimal places (0.0001°): roughly 11 m, enough to pick out a shoulder or lane area; Five decimal places (0.00001°): roughly 1.1 m, more precision than most phone GPS readings actually deliver
Longitude distances shrink as you move away from the equator, so these figures apply most directly to latitude. For a roadside call, four to five decimal places in decimal degrees is a practical target. Dropping digits or rounding heavily can move the reported point onto a different road.
How to find your coordinates
Where coordinates appear depends on the device, app version and, for built-in systems, the vehicle's model year and trim. The cues below are general; confirm the exact menu path in the documentation for your phone or vehicle.
Smartphone map apps: many show coordinates when you tap the blue current-location dot or press and hold on the map to drop a pin; the coordinates typically appear in the pin's detail panel and can often be copied; Smartphone compass apps: some display current latitude and longitude on the main compass screen when location services are enabled; Vehicle navigation systems: some factory head units show coordinates on a 'Where am I' or current-position screen; availability varies by manufacturer, model year and navigation package, so check the owner's manual; Connected-vehicle services: some vehicles with subscription telematics can transmit location to a call center directly; whether this is available depends on the vehicle, market and active subscription; Dedicated handheld or dash GPS units: usually show coordinates on a status or position screen
Before reading, give the device a moment to settle. GPS accuracy can degrade near tall buildings, in deep cuts or canyons, under heavy tree cover, and in or near tunnels. If the location dot shows a large accuracy circle, mention that the fix may be approximate.
How to read coordinates aloud
Clear delivery matters as much as the numbers. A consistent pattern helps the listener write them down correctly.
State the format first, for example: 'I have decimal-degree coordinates.'; Read latitude first, then longitude, and say each label; Read digits one at a time, and say 'point' for the decimal: 'three nine point seven three nine two zero'; Say the direction or sign explicitly: 'north' and 'west', or 'minus one zero four point...'; Ask the listener to read the numbers back, and correct any mismatch; If you can send a text, share the copied coordinates or a location pin as well as speaking them
Using the illustrative example above, a full readout would be: 'Latitude three nine point seven three nine two zero north. Longitude one zero four point nine nine zero three zero west.'
Mistakes that are easy to make
Swapping the order: reading longitude before latitude sends the listener to a completely different place; Dropping the minus sign or the W: in decimal form, a US longitude without its minus sign points to the Eastern Hemisphere; Mixing formats: reading decimal minutes as if they were decimal degrees produces a large error; Transposing digits: reading quickly increases the chance of swapping two numbers, which a read-back usually catches; Sharing stale coordinates: a screenshot or earlier pin may not match where the vehicle is now
Pair coordinates with roadside cues
Coordinates identify a point, but responders also need to know which side of a divided road you are on and how to reach you. Add whatever of the following you can see safely:
Road or highway name and direction of travel; Nearest mile marker, exit number or cross street; Which shoulder you are on, or whether you are in a lane, median or ramp; Vehicle make, model and color; Notable landmarks such as an overpass, bridge or business sign
When calling 911 from a mobile phone in the US, the network may provide an approximate location to the dispatcher, but the accuracy varies, so give your coordinates and road cues as well. Prioritize your safety while gathering any of this information; do not stand in or walk along live traffic lanes to read a sign.
Evidence note
This guide covers general, verifiable principles of coordinate formats and precision. No vehicle-specific, app-specific or service-specific specifications were available for it, so exact menu locations, telematics features and device accuracy should be checked against the documentation for your particular phone, app version and vehicle configuration.
