When an app asks for location permission, most people interpret that as the developer gaining access to wherever they go. That is not how it works. “Uses location” and “shares your location with the developer” are two different things, and conflating them leads to both unnecessary fear and misplaced trust.
This article explains how iOS location services actually function at the system level: what the hardware does, what iOS controls, and what any given app actually receives when you say yes to that permission prompt.
How iOS Location Services Work at the OS Layer
Location Services on iPhone is not an app. It is a system daemon called locationd that sits between the hardware and every app that wants location data. Apps do not talk to GPS directly. They make a request to the OS, and the OS decides what to give them.
The GPS hardware itself works by receiving signals broadcast from satellites orbiting the Earth. Your phone calculates its own position from those signals. No data is transmitted back to the satellites. The position calculation happens locally on your device.
iOS also uses other inputs to refine location: nearby Wi-Fi network identifiers, cell tower signals, and Bluetooth beacons. All of this is processed on-device by the OS. The combination of these signals is what makes location work accurately even in areas with poor GPS signal, like dense cities.
The key point is that locationd is the gatekeeper. An app cannot reach around it. What the OS decides to hand over is what the app gets, nothing more.
The Permission Model
When an app requests location, iOS gives you several choices:
When In Use grants access only while the app is actively open on screen or running in the foreground. The moment you leave the app, location access stops. This is the appropriate permission for the vast majority of apps: navigation, speedometers, weather lookups.
Always grants access even when the app is not visible. The app can check your location in the background without you knowing. This permission is appropriate for apps like Find My or fitness trackers, but it is overkill for most things that ask for it.
Allow Once grants access for a single session. The next time you open the app, it has to ask again. Useful for one-time needs where you do not want to think about revoking permissions later.
Precise vs. Approximate location is a separate toggle. Precise location gives an app your actual GPS coordinates. Approximate location gives a general area, roughly city-level accuracy. Turning off Precise Location for apps that only need to know your general region is a simple way to limit exposure while mostly not breaking functionality. A speedometer is different: apps like eyeSpeed need Precise Location enabled, because iOS derives speed from GPS position updates over time, and approximate location is not enough for a trustworthy readout.
The arrow icon that appears in your iPhone status bar is the location indicator. A solid arrow means an app is actively using your location right now. A hollow arrow means an app has accessed location in the recent past or has set up a geofence. If you see that indicator when no app you recognize should be using location, it is worth investigating in Settings.
To review or change any app’s location permission, go to Settings > Privacy & Security > Location Services.
What an App Actually Receives
When you grant location permission, iOS provides the app with a CLLocation object. That is a data structure containing the following fields at the moment of the request: coordinates (latitude and longitude), speed, course (direction of travel), altitude, horizontal and vertical accuracy estimates, and a timestamp.
What it does not include: your location history, a route, your identity, or any prior location data. Each CLLocation object is a snapshot of one moment. The app gets the snapshot; it does not get the log.
Importantly, permission is not a blank check. The developer has to actively write code to do something with that data. If they read only the speed field and display it on screen, that is all that happens. If they collect coordinates and send them to a server, that is a separate decision they made in their code.
The OS delivers the data. What the developer does with it after that is entirely up to them. That is the distinction that matters.
What Apple Collects Separately
One thing that is often confused in this conversation: Apple has its own location-related services running on your device, separate from any third-party app.
Features like Significant Locations, which powers Siri suggestions, Maps routing, and some personalization features, involve Apple tracking frequently visited places. This is Apple’s own data collection, and it operates independently of what any App Store app is doing.
If you want to disable it, go to Settings > Privacy & Security > Location Services > System Services, and you will find toggles for Apple’s own location features including Significant Locations.
It is worth being clear: when you see an App Store privacy label saying “Data Not Collected,” that refers to what the app developer collects. It says nothing about what Apple may collect through its own system services. Those are governed by Apple’s own privacy policy, not the app’s.
App Store Privacy Labels and Their Limits
Apple’s App Store privacy labels are a useful signal, but they have real limits worth understanding.
The “Data Not Collected” label means the developer has declared that they do not collect any data from the app. That includes location data, usage data, identifiers, and everything else in Apple’s taxonomy.
The limitation is that these labels are self-reported. Apple does not independently audit every app against its declared label. A developer fills out the privacy nutrition label when submitting the app. The label reflects what the developer says they do.
For most legitimate apps from credible developers, the label is accurate. But if you are evaluating a lesser-known app, it is worth reading the actual privacy policy as a second check. Look for specific language about what location data is collected, where it goes, and how long it is retained. Vague language like “we may share data with partners” is a warning sign regardless of what the label says.
How eyeSpeed Handles Location
eyeSpeed requests “When In Use” location permission. That is the most limited persistent access tier. It stops the moment you leave the app.
The only field eyeSpeed reads from CLLocation is speed. That is a scalar value in meters per second that iOS calculates from your GPS signal. eyeSpeed converts it to MPH or KPH and displays it on screen. That is the complete data flow.
No coordinates are stored. No route is built. No location data is transmitted to a server. There is no eyeSpeed account, so there is no way to associate your location with an identity on the back end even if something were sent (which it is not).
The “Data Not Collected” App Store label reflects this exactly: location data is not sent to eyeSpeed.
This is what it looks like when location is used as an input rather than an asset. GPS provides a speed signal. The app reads the signal, shows it, and discards it. There is no business reason to store where you have been, so it is not stored.
Practical Tips for Managing Location Privacy on iPhone
A few things worth doing periodically:
Review which apps have “Always” permission. Go to Settings > Privacy & Security > Location Services. Any app showing “Always” should have a genuine reason. If you do not know why it needs background access, change it to “When In Use.”
Turn off Precise Location for apps that do not need it. A weather app does not need your exact GPS coordinates. A food delivery app might need your address, but not continuous precise tracking. Flip Precise Location off for anything that does not have a clear need for it.
Use “Allow Once” for one-time needs. If you open an app rarely and it asks for location to function that one time, “Allow Once” is the right answer. You are not committed to anything ongoing.
Watch the status bar arrow. If you see the location indicator when no navigation or location-dependent app is obviously running, check what is active. It could be legitimate background activity or something worth questioning.
Review Location Services periodically. Things accumulate. An app you gave broad access to two years ago may not still warrant it.
Driving It Home
Location Services on iPhone is a system-level broker, not a direct pipeline from your GPS to a developer’s server. You control what each app can access. Each access is a snapshot, not a history. And the developer’s choices about what to do with that data are separate from the OS granting access in the first place.
Understanding this does not mean trusting every app. It means you have the information to evaluate them accurately.
For drivers who want a speedometer that treats location strictly as an input, search for eyeSpeed in the App Store.