Turning on GPRS/UMTS positioning if GPS does not work

[me.yahoo.com/a/ydgsnam6qn3qn6qlyad5jaihuw--#6ef80]

It should be great automatically switching to GPRS/UMTS positioning in tunnels where GPS does not work.

Looking into source code I found in NavitVehicle?.java: Once the GPRS positioning (preciseProvider) is working, GPRS/UMTS positioning (fastProvider) is turned off. A workaround might be turning on the fastProvider again, if GPS is manually disabled. This should be simple to implement.

Suggestion of implementation for the following method in ​https://navit.svn.sourceforge.net/svnroot/navit/trunk/navit/navit/android/src/org/navitproject/navit/NavitVehicle.java:

[...]
private final LocationListener preciseLocationListener = new LocationListener() {
[...]
  // Turning GPRS/UMTS positioning on again, if GPS is (manually) disabled.
  public void onProviderDisabled(String provider) {
    if (fastProvider == null) {
      // Selection criteria for the fast provider
      Criteria lowCriteria = new Criteria();
      lowCriteria.setAccuracy(Criteria.ACCURACY_COARSE);
      lowCriteria.setAltitudeRequired(false);
      lowCriteria.setBearingRequired(false);
      lowCriteria.setCostAllowed(true);
      lowCriteria.setPowerRequirement(Criteria.POWER_HIGH);
      String tmpFastProvider = locationManager.getBestProvider(lowCriteria, false);
      if (tmpFastProvider!=null && 
preciseProvider.compareTo(tmpFastProvider) != 0) {
        fastProvider = tmpFastProvider;
        locationManager.requestLocationUpdates(fastProvider, 0, 0, 
fastLocationListener);
      }
    }
  }
[...]
};
[...]

[usul]

This includes various tasks if it should be supported crossplattform:

• components to read cellid from devices
• find/create a positioning service that offers cellid DB
• create algorithm to find the corresponding position within tunnels, underground, buildings, ...

Will take a lot of time, but maybe Android can be a first step. Anyway, will set it to the next release as a first step.