System Location Master list

[Armen]

This information is all over the place so I'm going to put it in plain sight.

Settings > privacy > location services > system services:

Cell Network Search: This has nothing to do with the Phone connecting to a cell tower. This feature allows your iPhone to send Apple locations of cell towers. Apple keeps its own database of cell towers aside from the Carrier. ( I have this OFF)

Compass Caliberation: The Compass Calibration is used to determine where on the Earth you are so that north can be set for true north (I have it OFF)

Diagnostics & Usage: This is related to the "send diagnostics" option under the settings section. Apple uses this info to improve its products. ( I have this OFF)

Location based iAds: If you have this on you're supposed to only see ads relative to your location. (I have this OFF)

Popular Near Me: When you download an app Apple notes where you were when you downloaded it to share it with other people in your area that may benefit from that app as well. (like a NYC transit app if you are visiting NYC) (I have this OFF)

Setting Time Zone: This will set your clock based on where you are located. If you do not travel much you can turn this off. (I have this OFF)

Traffic: This is not to be confused with the "show Traffic" option in Apple maps.This sends Traffic data to Apple. (I have set to Off)
Wi-Fi Networking: This sends Wifi hotspot locations in your area to Apple for whatever purpose. (I have this OFF)

Frequent Locations: This tracks where you visit frequently to help determine traffic when you travel in the notifications area under next destination. (I have this ON)

 

[Intell]

Compass Caliberation: The compass app uses this service to display your GPS coordinates. (I have this OFF)

This one would be incorrect. The Compass Calibration is used to determine where on the Earth you are so that north can be set for true north. All electronic compasses need to be calibrated for their geographical location. The calibration zones are roughly the same size and area as time zones. If you vehicle has a compass, read its manual on how to set the compass for a little diagram of them and how it works. The Compass app has its own location settings with the rest of the apps.

 

[Armen]

This one would be incorrect. The Compass Calibration is used to determine where on the Earth you are so that north can be set for true north. All electronic compasses need to be calibrated for their geographical location. The calibration zones are roughly the same size and area as time zones. If you vehicle has a compass, read its manual on how to set the compass for a little diagram of them and how it works. The Compass app has its own location settings with the rest of the apps.

Fixed. Thank you.

 

[SanjeevRana]

And this is not a one-way transfer ..

Cell Network Search: This has nothing to do with the Phone connecting to a cell tower. This feature allows your iPhone to send Apple locations of cell towers. Apple keeps its own database of cell towers aside from the Carrier. ( I have this OFF)

When u come off Airplane mode or start the phone, Location is used to determine best searching criteria for a cell tower. How much this helps, only Apple knows

 

[Squid7085]

I believe traffic is wrong too, I am pretty sure that has to do with allowing your device to SEND traffic data to Apple. That is how Apple gets that traffic data, using the "speed" of all the iPhones traveling down a particular road relative to the posted speed.

WiFi is sending location data about nearby networks to help triangulate a location better. GPS may not work in the mall, but using wifi locations your phone can know where you are in the mall. That's what that does.