Retrieving the user location - a quick overview - Anton Rademaker's Blog - Software Engineering

Location based services are one likely to be next generation killer applications. Determining the location of the user can be done in various ways: using GPS (Global Positioning System), the cell id the user is currently connected to (GSM), WLAN and Bluetooth. To enable easier development of such services based, the two main mobile operating systems offer location API's. Microsoft's Windows Mobile 5 operating system provides the GPS Intermediate Driver API and Symbian Series 60 includes the Location Acquisition API. The GPS Intermediate Driver is an abstraction layer between applications and hardware. It provides two methods to access the data: a raw method and a parsed method. Most GPS devices use the NMEA interface protocol. The raw method can be used to directly interface with the GPS device using NMEA. The parsed method hides the use of NMEA and offers functions like GPSGetPosition to retrieve a GPS position struct containing information about for example the location, speed, fix and accuracy.
The Location Acquisition API is part of the Series 60 platform 2.6 and higher. The API is based on the client-server pattern. One of the biggest differences with Microsoft's API is the number of functions provided. Symbian provides for all attributes of the location a function whereas Microsoft uses a struct containing all information.
Both API's provide the location of the user using GPS.


Third-party alternatives

Other parties also invented location API's. These API's are often more dedicated to a programming platform: Java or .Net but also offer more options.
The JSR 179 Location API is written in Java for the Symbian OS and provides more advanced options like for example in some cases the address information. The API cannot only retrieve the location by GPS, but also supports retrieving the location using the cell id or WLAN/Bluetooth.
For the .Net platform, GeoFrameworks has developed an API: GPS.net. This API is although not free: developers must buy a developer kit. It's a very simple API, parsing of the NMEA has to be done by the developer himself.

This entry was posted by Anton Rademaker on Sunday, February 26. 2006 at 22:20. and is filed under Mobile Software. You can leave a response, or trackback from your own blog.

location based services