[gps] Don't correct for true north by default, and add manual bearing…

… offset option This change adds two new advanced settings keys for gps: app\gps\bearingAdjustment: allows for specifying a manual adjustment factor to apply to bearings obtained from the GPS, in the case that the GPS reports offset bearings app\gps\correctForTrueNorth: whether to apply a correction for true north to bearings obtained from the GPS (now defaults to off)
qgis · May 30, 2020 · f5e55df · f5e55df
1 parent 81abbbb
commit f5e55df
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Showing 2 changed files with 22 additions and 7 deletions.
diff --git a/resources/qgis_global_settings.ini b/resources/qgis_global_settings.ini
@@ -86,6 +86,16 @@ projections\newProjectCrsBehavior=UseCrsOfFirstLayerAdded
 # "UseDefaultCrs" - use the default layer CRS set via QGIS options
 projections\unknownCrsBehavior=NoAction
 
+# Specifies a manual bearing correction to apply to bearings reported by a GPS
+# device, for use when a map canvas is set to match rotation to the GPS bearing
+# or when showing the GPS bearing line
+gps\bearingAdjustment=0
+
+# Set to "true" to automatically correct GPS reported bearings for true north
+# when a map canvas is set to match rotation to the GPS bearing
+# or when showing the GPS bearing line
+gps\correctForTrueNorth=false
+
 [core]
 
 # Desired flow control mode for serial port GPS connections

diff --git a/src/app/gps/qgsgpsinformationwidget.cpp b/src/app/gps/qgsgpsinformationwidget.cpp
@@ -1002,18 +1002,23 @@ void QgsGpsInformationWidget::displayGPSInformation( const QgsGpsInformation &in
   if ( !std::isnan( info.direction ) )
   {
     double trueNorth = 0;
-    try
-    {
-      trueNorth = QgsBearingUtils::bearingTrueNorth( mMapCanvas->mapSettings().destinationCrs(), QgsProject::instance()->transformContext(), mMapCanvas->mapSettings().visibleExtent().center() );
-    }
-    catch ( QgsException & )
+    QgsSettings settings;
+    if ( settings.value( QStringLiteral( "gps/correctForTrueNorth" ), false, QgsSettings::App ).toBool() )
     {
+      try
+      {
+        trueNorth = QgsBearingUtils::bearingTrueNorth( mMapCanvas->mapSettings().destinationCrs(), QgsProject::instance()->transformContext(), mMapCanvas->mapSettings().visibleExtent().center() );
+      }
+      catch ( QgsException & )
+      {
 
+      }
     }
+    const double adjustment = settings.value( QStringLiteral( "gps/bearingAdjustment" ), 0.0, QgsSettings::App ).toDouble();
 
     if ( mRotateMapCheckBox->isChecked() && ( !mLastRotateTimer.isValid() || mLastRotateTimer.hasExpired( mSpinMapRotateInterval->value() * 1000 ) ) )
     {
-      mMapCanvas->setRotation( trueNorth - info.direction );
+      mMapCanvas->setRotation( trueNorth - info.direction - adjustment );
       mLastRotateTimer.restart();
     }
 
@@ -1026,7 +1031,7 @@ void QgsGpsInformationWidget::displayGPSInformation( const QgsGpsInformation &in
       }
 
       mMapBearingItem->setGpsPosition( myNewCenter );
-      mMapBearingItem->setGpsBearing( info.direction - trueNorth );
+      mMapBearingItem->setGpsBearing( info.direction - trueNorth + adjustment );
     }
     else if ( mMapBearingItem )
     {