Difference between revisions of "Location Based Services"

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Modern mobile phones store geographic information, GPS coordinates, wifi networks, mobile cells.
 
Modern mobile phones store geographic information, GPS coordinates, wifi networks, mobile cells.
  
== IOS ==
+
= IOS =
  
 
* Stores wifi networks:
 
* Stores wifi networks:
Line 12: Line 12:
 
* Data used ..?
 
* Data used ..?
  
== Android ==
+
= Android =
=== Information stored ===
+
Android's location services stores information for caching reasons in two database files to speed up your GPS fix.
==== Location on your device ====
+
== Information stored ==
 +
=== Location on your device ===
 
* /data/data/com.google.android.location/files
 
* /data/data/com.google.android.location/files
 
** cache.wifi
 
** cache.wifi
 
** cache.cell
 
** cache.cell
  
==== How much get's stored ====
+
=== Database ===
 
* Database is limited to:
 
* Database is limited to:
 
** 200 Wi-Fi entries
 
** 200 Wi-Fi entries
 
** 50 Cell entries
 
** 50 Cell entries
 +
{| border="1" cellspacing="0" cellpadding="5"
 +
|Value || Type || Description
 +
|-
 +
|key || || '''cell:''' mcc + ":" + mnc + ":" + lac + ":" + cid <br /> '''Wi-Fi:''' BSSID
 +
|-
 +
|accuracy || int ||
 +
|-
 +
|confidence || int ||
 +
|-
 +
|latitude || double ||
 +
|-
 +
|longitude || double ||
 +
|-
 +
|readingTime || long ||
 +
|}
  
=== Settings ===
+
== Settings ==
 
* Settings -> Location & Security -> Use wireless networks
 
* Settings -> Location & Security -> Use wireless networks
 
** when ticked: stores information in two databases
 
** when ticked: stores information in two databases
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File:android_location_confirm.png|Google informs you that they will use your information
 
File:android_location_confirm.png|Google informs you that they will use your information
 
</gallery>
 
</gallery>
 +
 +
== How to disable the cache ==
 +
There are two ways to "disable" prevent your phone from storing caching information on your device.
 +
=== First method ===
 +
Your can disable the whole caching process by un-ticking '''Use wireless networks''' under '''Settings -> Location & Security -> Use wireless networks'''. But this may slow down your GPS fix.
 +
 +
=== Second method (requires a rooted phone) ===
 +
You can prevent that the location service writes to the said two files with
 +
* '''chmod 000 /data/data/com.google.android.location/files/cache.wifi'''
 +
* '''chmod 000 /data/data/com.google.android.location/files/cache.cell'''
 +
 +
= Windows Mobile =

Latest revision as of 11:41, 27 April 2011

Modern mobile phones store geographic information, GPS coordinates, wifi networks, mobile cells.

IOS

  • Stores wifi networks:
    • BSSID, Location, Accuracy, Timestamp, ...
  • Stores mobile geo information:
    • your providers cell towers, Cell Numer, Location, ...
  • Database without size limit
  • Sends data how?
  • Correlates with GPS
  • Data used ..?

Android

Android's location services stores information for caching reasons in two database files to speed up your GPS fix.

Information stored

Location on your device

  • /data/data/com.google.android.location/files
    • cache.wifi
    • cache.cell

Database

  • Database is limited to:
    • 200 Wi-Fi entries
    • 50 Cell entries
Value Type Description
key cell: mcc + ":" + mnc + ":" + lac + ":" + cid
Wi-Fi: BSSID
accuracy int
confidence int
latitude double
longitude double
readingTime long

Settings

  • Settings -> Location & Security -> Use wireless networks
    • when ticked: stores information in two databases
    • when un-ticked: no information get's stored on your device

How to disable the cache

There are two ways to "disable" prevent your phone from storing caching information on your device.

First method

Your can disable the whole caching process by un-ticking Use wireless networks under Settings -> Location & Security -> Use wireless networks. But this may slow down your GPS fix.

Second method (requires a rooted phone)

You can prevent that the location service writes to the said two files with

  • chmod 000 /data/data/com.google.android.location/files/cache.wifi
  • chmod 000 /data/data/com.google.android.location/files/cache.cell

Windows Mobile