Position +Area Data Classes

diff -r 43e37759235e -r 51a74ef9ed63 Symbian3/SDK/Source/GUID-70E1117B-17F0-5CF4-A5D0-35D3BEBB0FEA.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Symbian3/SDK/Source/GUID-70E1117B-17F0-5CF4-A5D0-35D3BEBB0FEA.dita Wed Mar 31 11:11:55 2010 +0100 @@ -0,0 +1,60 @@ + + + + + +Position +Area Data ClassesThis document describes the basic and extended position area data +classes that contain information about the accuracy of the position returned +to an application when it calls RPositioner::GetLastKnownPositionArea(). +

LBS maintains a cache of previously calculated position fixes. If an application +calls RPositioner::GetLastKnownLocation(), LBS returns +the most recently calculated position. If an application calls RPositioner::GetLastKnownPositionArea(), +LBS returns the position fix that is the best match for the current location +of the mobile device. The current location of the mobile device is estimated +from data received from the network.

The Location Acquisition API defines a set of position area data classes +(figure 1). A client application passes an object of one of these classes +as a parameter when it calls RPositioner::GetLastKnownPositionArea(). +The position area data classes are defined in LbsAreaInfo.h.

+ + Figure 1. Position Area Data Classes. + + +

A brief description of the classes follows. Follow the links to more detailed +reference documentation.

TPositionAreaInfoBase is +the base class of the position area data classes. Applications create an object +of one of the derived classes.
TPositionAreaInfo contains +basic information about the accuracy of a returned position. Its defines an +enumerated type TPositionAreaInfo::_TArea that defines +an estimate of how closely the current device position matches the returned +position. The position accuracy estimate can be from country level down to +street level, depending on how much information is available from the network.
TPositionAreaExtendedInfo extends TPositionAreaInfo to +provide details about how the accuracy estimate of the returned position was +calculated.

An accuracy estimate can be obtained from the network +as some combination of the following:
- Mobile Country Code
- Mobile Network Code
- Location Area Code
- Cell ID
LBS uses combinations of the above to derive the accuracy estimate +returned from TPositionAreaInfo::Area(). Your application +can find what types of data were used to calculate the accuracy estimate by +passing an object of class TPositionAreaExtendedInfo to RPositioner::GetLastKnownLocationArea() and +then using the methods shown in figure 1 to check for code and ID matches.

+ +How to Get +Location Information +

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