Add new FactGroup support

Plumb through initial object mode on Vehicle

qgroundcontrol.pro

@@ -673,6 +673,7 @@ INCLUDEPATH += \
 
 HEADERS += \
     src/FactSystem/Fact.h \
+    src/FactSystem/FactGroup.h \
     src/FactSystem/FactControls/FactPanelController.h \
     src/FactSystem/FactMetaData.h \
     src/FactSystem/FactSystem.h \
@@ -682,6 +683,7 @@ HEADERS += \
 
 SOURCES += \
     src/FactSystem/Fact.cc \
+    src/FactSystem/FactGroup.cc \
     src/FactSystem/FactControls/FactPanelController.cc \
     src/FactSystem/FactMetaData.cc \
     src/FactSystem/FactSystem.cc \

qgroundcontrol.qrc

@@ -148,5 +148,8 @@
         <file alias="PX4/MavCmdInfoCommon.json">src/FirmwarePlugin/PX4/MavCmdInfoCommon.json</file>
         <file alias="PX4/MavCmdInfoFixedWing.json">src/FirmwarePlugin/PX4/MavCmdInfoFixedWing.json</file>
         <file alias="PX4/MavCmdInfoMultiRotor.json">src/FirmwarePlugin/PX4/MavCmdInfoMultiRotor.json</file>
+        <file alias="Vehicle/VehicleFact.json">src/Vehicle/VehicleFact.json</file>
+        <file alias="Vehicle/BatteryFact.json">src/Vehicle/BatteryFact.json</file>
+        <file alias="Vehicle/GPSFact.json">src/Vehicle/GPSFact.json</file>
     </qresource>
 </RCC>

src/FactSystem/Fact.cc

@@ -35,6 +35,8 @@ Fact::Fact(QObject* parent)
     , _rawValue(0)
     , _type(FactMetaData::valueTypeInt32)
     , _metaData(NULL)
+    , _sendValueChangedSignals(true)
+    , _deferredValueChangeSignal(false)
 {    
     FactMetaData* metaData = new FactMetaData(_type, this);
     setMetaData(metaData);
@@ -47,6 +49,8 @@ Fact::Fact(int componentId, QString name, FactMetaData::ValueType_t type, QObjec
     , _rawValue(0)
     , _type(type)
     , _metaData(NULL)
+    , _sendValueChangedSignals(true)
+    , _deferredValueChangeSignal(false)
 {
     FactMetaData* metaData = new FactMetaData(_type, this);
     setMetaData(metaData);
@@ -60,11 +64,13 @@ Fact::Fact(const Fact& other, QObject* parent)
 
 const Fact& Fact::operator=(const Fact& other)
 {
-    _name           = other._name;
-    _componentId    = other._componentId;
-    _rawValue          = other._rawValue;
-    _type           = other._type;
-    
+    _name                       = other._name;
+    _componentId                = other._componentId;
+    _rawValue                   = other._rawValue;
+    _type                       = other._type;
+    _sendValueChangedSignals    = other._sendValueChangedSignals;
+    _deferredValueChangeSignal  = other._deferredValueChangeSignal;
+
     if (_metaData && other._metaData) {
         *_metaData = *other._metaData;
     } else {
@@ -82,7 +88,7 @@ void Fact::forceSetRawValue(const QVariant& value)
         
         if (_metaData->convertAndValidateRaw(value, true /* convertOnly */, typedValue, errorString)) {
             _rawValue.setValue(typedValue);
-            emit valueChanged(cookedValue());
+            _sendValueChangedSignal(cookedValue());
             emit _containerRawValueChanged(rawValue());
         }
     } else {
@@ -99,7 +105,7 @@ void Fact::setRawValue(const QVariant& value)
         if (_metaData->convertAndValidateRaw(value, true /* convertOnly */, typedValue, errorString)) {
             if (typedValue != _rawValue) {
                 _rawValue.setValue(typedValue);
-                emit valueChanged(cookedValue());
+                _sendValueChangedSignal(cookedValue());
                 emit _containerRawValueChanged(rawValue());
             }
         }
@@ -141,7 +147,7 @@ void Fact::setEnumIndex(int index)
 void Fact::_containerSetRawValue(const QVariant& value)
 {
     _rawValue = value;
-    emit valueChanged(cookedValue());
+    _sendValueChangedSignal(cookedValue());
     emit vehicleUpdated(_rawValue);
 }
 
@@ -492,3 +498,29 @@ bool Fact::rebootRequired(void) const
         return false;
     }
 }
+
+void Fact::setSendValueChangedSignals (bool sendValueChangedSignals)
+{
+    if (sendValueChangedSignals != _sendValueChangedSignals) {
+        _sendValueChangedSignals = sendValueChangedSignals;
+        emit sendValueChangedSignalsChanged(_sendValueChangedSignals);
+    }
+}
+
+void Fact::_sendValueChangedSignal(QVariant value)
+{
+    if (_sendValueChangedSignals) {
+        emit valueChanged(value);
+        _deferredValueChangeSignal = false;
+    } else {
+        _deferredValueChangeSignal = true;
+    }
+}
+
+void Fact::sendDeferredValueChangedSignal(void)
+{
+    if (_deferredValueChangeSignal) {
+        _deferredValueChangeSignal = false;
+        emit valueChanged(cookedValue());
+    }
+}

src/FactSystem/Fact.h

@@ -117,6 +117,15 @@ public:
     void setEnumIndex       (int index);
     void setEnumStringValue (const QString& value);
 
+    // The following methods allow you to defer sending of the valueChanged signals in order to implement
+    // rate limited signalling for ui performance. Used by FactGroup for example.
+
+    void setSendValueChangedSignals (bool sendValueChangedSignals);
+    bool sendValueChangedSignals (void) const { return _sendValueChangedSignals; }
+    bool deferredValueChangeSignal(void) const { return _deferredValueChangeSignal; }
+    void clearDeferredValueChangeSignal(void) { _deferredValueChangeSignal = false; }
+    void sendDeferredValueChangedSignal(void);
+
     // C++ methods
 
     /// Sets and sends new value to vehicle even if value is the same
@@ -129,12 +138,14 @@ public:
     
     /// Generally you should not change the name of a fact. But if you know what you are doing, you can.
     void _setName(const QString& name) { _name = name; }
+
     
 signals:
     void bitmaskStringsChanged(void);
     void bitmaskValuesChanged(void);
     void enumStringsChanged(void);
     void enumValuesChanged(void);
+    void sendValueChangedSignalsChanged(bool sendValueChangedSignals);
 
     /// QObject Property System signal for value property changes
     ///
@@ -151,12 +162,15 @@ signals:
     
 protected:
     QString _variantToString(const QVariant& variant) const;
+    void _sendValueChangedSignal(QVariant value);
 
     QString                     _name;
     int                         _componentId;
     QVariant                    _rawValue;
     FactMetaData::ValueType_t   _type;
     FactMetaData*               _metaData;
+    bool                        _sendValueChangedSignals;
+    bool                        _deferredValueChangeSignal;
 };
 
 #endif

src/FactSystem/FactGroup.cc

+/*=====================================================================
+ 
+ QGroundControl Open Source Ground Control Station
+ 
+ (c) 2009 - 2014 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+ 
+ This file is part of the QGROUNDCONTROL project
+ 
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+ 
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ 
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+ 
+ ======================================================================*/
+
+#include "FactGroup.h"
+#include "JsonHelper.h"
+
+#include <QJsonDocument>
+#include <QJsonParseError>
+#include <QJsonArray>
+#include <QDebug>
+#include <QFile>
+
+QGC_LOGGING_CATEGORY(FactGroupLog, "FactGroupLog")
+
+const char* FactGroup::_decimalPlacesJsonKey =      "decimalPlaces";
+const char* FactGroup::_nameJsonKey =               "name";
+const char* FactGroup::_propertiesJsonKey =         "properties";
+const char* FactGroup::_versionJsonKey =            "version";
+const char* FactGroup::_typeJsonKey =               "type";
+const char* FactGroup::_shortDescriptionJsonKey =   "shortDescription";
+const char* FactGroup::_unitsJsonKey =              "units";
+
+FactGroup::FactGroup(int updateRateMsecs, const QString& metaDataFile, QObject* parent)
+    : QObject(parent)
+    , _updateRateMSecs(updateRateMsecs)
+{
+    if (_updateRateMSecs > 0) {
+        connect(&_updateTimer, &QTimer::timeout, this, &FactGroup::_updateAllValues);
+        _updateTimer.setSingleShot(false);
+        _updateTimer.start(_updateRateMSecs);
+    }
+
+    _loadMetaData(metaDataFile);
+}
+
+Fact* FactGroup::getFact(const QString& name)
+{
+    if (_nameToFactMap.contains(name)) {
+        return _nameToFactMap[name];
+    } else {
+        qWarning() << "Unknown Fact" << name;
+    }
+
+    return NULL;
+}
+
+FactGroup* FactGroup::getFactGroup(const QString& name)
+{
+    if (_nameToFactGroupMap.contains(name)) {
+        return _nameToFactGroupMap[name];
+    } else {
+        qWarning() << "Unknown FactGroup" << name;
+    }
+
+    // FIXME: Return bogus fact
+    return NULL;
+}
+
+void FactGroup::_addFact(Fact* fact, const QString& name)
+{
+    if (_nameToFactMap.contains(name)) {
+        qWarning() << "Duplicate Fact" << name;
+        return;
+    }
+
+    fact->setSendValueChangedSignals(_updateRateMSecs == 0);
+    if (_nameToFactMetaDataMap.contains(name)) {
+        fact->setMetaData(_nameToFactMetaDataMap[name]);
+    }
+    _nameToFactMap[name] = fact;
+}
+
+void FactGroup::_addFactGroup(FactGroup* factGroup, const QString& name)
+{
+    if (_nameToFactGroupMap.contains(name)) {
+        qWarning() << "Duplicate FactGroup" << name;
+        return;
+    }
+
+    _nameToFactGroupMap[name] = factGroup;
+}
+
+void FactGroup::_updateAllValues(void)
+{
+    foreach(Fact* fact, _nameToFactMap) {
+        fact->sendDeferredValueChangedSignal();
+    }
+}
+
+void FactGroup::_loadMetaData(const QString& jsonFilename)
+{
+    if (jsonFilename.isEmpty()) {
+        return;
+    }
+
+    qCDebug(FactGroupLog) << "Loading" << jsonFilename;
+
+    QFile jsonFile(jsonFilename);
+    if (!jsonFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        qWarning() << "Unable to open file" << jsonFilename << jsonFile.errorString();
+        return;
+    }
+
+    QByteArray bytes = jsonFile.readAll();
+    jsonFile.close();
+    QJsonParseError jsonParseError;
+    QJsonDocument doc = QJsonDocument::fromJson(bytes, &jsonParseError);
+    if (jsonParseError.error != QJsonParseError::NoError) {
+        qWarning() <<  "Unable to open json document" << jsonFilename << jsonParseError.errorString();
+        return;
+    }
+
+    QJsonObject json = doc.object();
+
+    int version = json.value(_versionJsonKey).toInt();
+    if (version != 1) {
+        qWarning() << "Invalid version" << version;
+        return;
+    }
+
+    QJsonValue jsonValue = json.value(_propertiesJsonKey);
+    if (!jsonValue.isArray()) {
+        qWarning() << "properties object not array";
+        return;
+    }
+
+    QJsonArray jsonArray = jsonValue.toArray();
+    foreach(QJsonValue property, jsonArray) {
+        if (!property.isObject()) {
+            qWarning() << "properties object should contain only objects";
+            return;
+        }
+        QJsonObject jsonObject = property.toObject();
+
+        // Make sure we have the required keys
+        QString errorString;
+        QStringList requiredKeys;
+        requiredKeys << _nameJsonKey << _decimalPlacesJsonKey << _typeJsonKey << _shortDescriptionJsonKey;
+        if (!JsonHelper::validateRequiredKeys(jsonObject, requiredKeys, errorString)) {
+            qWarning() << errorString;
+            return;
+        }
+
+        // Validate key types
+
+        QStringList             keys;
+        QList<QJsonValue::Type> types;
+        keys << _nameJsonKey << _decimalPlacesJsonKey;
+        types << QJsonValue::String << QJsonValue::Double;
+        if (!JsonHelper::validateKeyTypes(jsonObject, keys, types, errorString)) {
+            qWarning() << errorString;
+            return;
+        }
+
+        QString name = jsonObject.value(_nameJsonKey).toString();
+        if (_nameToFactMetaDataMap.contains(name)) {
+            qWarning() << "Duplicate property name" << name;
+            continue;
+        }
+
+        bool unknownType;
+        FactMetaData::ValueType_t type = FactMetaData::stringToType(jsonObject.value(_typeJsonKey).toString(), unknownType);
+        if (unknownType) {
+            qWarning() << "Unknown type" << jsonObject.value(_typeJsonKey).toString();
+            return;
+        }
+
+        QStringList enumValues, enumStrings;
+        if (!JsonHelper::parseEnum(jsonObject, enumStrings, enumValues, errorString)) {
+            qWarning() << errorString;
+            return;
+        }
+
+        FactMetaData* metaData = new FactMetaData(type, this);
+
+        metaData->setDecimalPlaces(jsonObject.value(_decimalPlacesJsonKey).toInt());
+        metaData->setShortDescription(jsonObject.value(_shortDescriptionJsonKey).toString());
+        metaData->setRawUnits(jsonObject.value(_unitsJsonKey).toString());
+
+        for (int i=0; i<enumValues.count(); i++) {
+            QVariant    enumVariant;
+            QString     errorString;
+
+            if (metaData->convertAndValidateRaw(enumValues[i], false /* validate */, enumVariant, errorString)) {
+                metaData->addEnumInfo(enumStrings[i], enumVariant);
+            } else {
+                qWarning() << "Invalid enum value, name:" << metaData->name()
+                            << " type:" << metaData->type() << " value:" << enumValues[i]
+                            << " error:" << errorString;
+                delete metaData;
+                return;
+            }
+        }
+
+        _nameToFactMetaDataMap[name] = metaData;
+    }
+}

src/FactSystem/FactGroup.h

+/*=====================================================================
+ 
+ QGroundControl Open Source Ground Control Station
+ 
+ (c) 2009 - 2014 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+ 
+ This file is part of the QGROUNDCONTROL project
+ 
+ QGROUNDCONTROL is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+ 
+ QGROUNDCONTROL is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ 
+ You should have received a copy of the GNU General Public License
+ along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
+ 
+ ======================================================================*/
+
+#ifndef FactGroup_H
+#define FactGroup_H
+
+#include "Fact.h"
+#include "QGCLoggingCategory.h"
+
+#include <QStringList>
+#include <QMap>
+#include <QTimer>
+
+Q_DECLARE_LOGGING_CATEGORY(VehicleLog)
+
+/// Used to group Facts together into an object hierarachy.
+class FactGroup : public QObject
+{
+    Q_OBJECT
+    
+public:
+    FactGroup(int updateRateMsecs, const QString& metaDataFile, QObject* parent = NULL);
+
+    Q_PROPERTY(QStringList factNames        READ factNames      CONSTANT)
+    Q_PROPERTY(QStringList factGroupNames   READ factGroupNames CONSTANT)
+
+    /// @return Fact for specified name, NULL if not found
+    Q_INVOKABLE Fact* getFact(const QString& name);
+
+    /// @return FactGroup for specified name, NULL if not found
+    Q_INVOKABLE FactGroup* getFactGroup(const QString& name);
+
+    QStringList factNames(void) const { return _nameToFactMap.keys(); }
+    QStringList factGroupNames(void) const { return _nameToFactGroupMap.keys(); }
+    
+protected:
+    void _addFact(Fact* fact, const QString& name);
+    void _addFactGroup(FactGroup* factGroup, const QString& name);
+
+    int _updateRateMSecs;   ///< Update rate for Fact::valueChanged signals, 0: immediate update
+
+private slots:
+    void _updateAllValues(void);
+
+private:
+    void _loadMetaData(const QString& filename);
+
+    QMap<QString, Fact*>            _nameToFactMap;
+    QMap<QString, FactGroup*>       _nameToFactGroupMap;
+    QMap<QString, FactMetaData*>    _nameToFactMetaDataMap;
+
+    QTimer _updateTimer;
+
+    static const char*  _propertiesJsonKey;
+    static const char*  _nameJsonKey;
+    static const char*  _decimalPlacesJsonKey;
+    static const char*  _typeJsonKey;
+    static const char*  _versionJsonKey;
+    static const char*  _shortDescriptionJsonKey;
+    static const char*  _unitsJsonKey;
+};
+
+#endif

src/FactSystem/FactMetaData.cc

@@ -398,3 +398,39 @@ void FactMetaData::setRawUnits(const QString& rawUnits)
 
     _setBuiltInTranslator();
 }
+
+FactMetaData::ValueType_t FactMetaData::stringToType(const QString& typeString, bool& unknownType)
+{
+    QStringList         knownTypeStrings;
+    QList<ValueType_t>  knownTypes;
+
+    unknownType = false;
+
+    knownTypeStrings << QStringLiteral("Uint8")
+                        << QStringLiteral("Int8")
+                        << QStringLiteral("Uint16")
+                        << QStringLiteral("Int16")
+                        << QStringLiteral("Uint32")
+                        << QStringLiteral("Int32")
+                        << QStringLiteral("Float")
+                        << QStringLiteral("Double");
+
+    knownTypes << valueTypeUint8
+                << valueTypeInt8
+                << valueTypeUint16
+                << valueTypeInt16
+                << valueTypeUint32
+                << valueTypeInt32
+                << valueTypeFloat
+                << valueTypeDouble;
+
+    for (int i=0; i<knownTypeStrings.count(); i++) {
+        if (knownTypeStrings[i].compare(typeString, Qt::CaseInsensitive) == 0) {
+            return knownTypes[i];
+        }
+    }
+
+    unknownType = true;
+
+    return valueTypeDouble;
+}

src/FactSystem/FactMetaData.h

@@ -120,6 +120,8 @@ public:
 
     static const int defaultDecimalPlaces = 3;
 
+    static ValueType_t stringToType(const QString& typeString, bool& unknownType);
+
 private:
     QVariant _minForType(void) const;
     QVariant _maxForType(void) const;

src/FactSystem/FactSystem.cc

@@ -25,6 +25,7 @@
 ///     @author Don Gagne <don@thegagnes.com>
 
 #include "FactSystem.h"
+#include "FactGroup.h"
 #include "FactPanelController.h"
 
 #include <QtQml>
@@ -41,6 +42,7 @@ void FactSystem::setToolbox(QGCToolbox *toolbox)
 {
     QGCTool::setToolbox(toolbox);
 
-    qmlRegisterType<Fact>(_factSystemQmlUri, 1, 0, "Fact");
+    qmlRegisterType<Fact>               (_factSystemQmlUri, 1, 0, "Fact");
+    qmlRegisterType<Fact>               (_factSystemQmlUri, 1, 0, "FactGroup");
     qmlRegisterType<FactPanelController>(_factSystemQmlUri, 1, 0, "FactPanelController");
 }

src/FlightDisplay/FlightDisplayView.qml

@@ -36,6 +36,7 @@ import QGroundControl.Controls      1.0
 import QGroundControl.Palette       1.0
 import QGroundControl.Vehicle       1.0
 import QGroundControl.Controllers   1.0
+import QGroundControl.FactSystem    1.0
 
 /// Flight Display View
 Item {
@@ -55,7 +56,6 @@ Item {
     readonly property real _defaultAltitudeWGS84:       0
     readonly property real _defaultGroundSpeed:         0
     readonly property real _defaultAirSpeed:            0
-    readonly property real _defaultClimbRate:           0
 
     readonly property string _mapName:                  "FlightDisplayView"
     readonly property string _showMapBackgroundKey:     "/showMapBackground"
@@ -65,14 +65,15 @@ Item {
     property bool _mainIsMap:           QGroundControl.loadBoolGlobalSetting(_mainIsMapKey,  true)
     property bool _isPipVisible:        QGroundControl.loadBoolGlobalSetting(_PIPVisibleKey, true)
 
-    property real _roll:                _activeVehicle ? (isNaN(_activeVehicle.roll)    ? _defaultRoll    : _activeVehicle.roll)    : _defaultRoll
-    property real _pitch:               _activeVehicle ? (isNaN(_activeVehicle.pitch)   ? _defaultPitch   : _activeVehicle.pitch)   : _defaultPitch
-    property real _heading:             _activeVehicle ? (isNaN(_activeVehicle.heading) ? _defaultHeading : _activeVehicle.heading) : _defaultHeading
+    property real _roll:                _activeVehicle ? _activeVehicle.roll.value    : _defaultRoll
+    property real _pitch:               _activeVehicle ? _activeVehicle.pitch.value   : _defaultPitch
+    property real _heading:             _activeVehicle ? _activeVehicle.heading.value : _defaultHeading
 
-    property real _altitudeWGS84:       _activeVehicle ? _activeVehicle.altitudeWGS84 : _defaultAltitudeWGS84
-    property real _groundSpeed:         _activeVehicle ? _activeVehicle.groundSpeed   : _defaultGroundSpeed
-    property real _airSpeed:            _activeVehicle ? _activeVehicle.airSpeed      : _defaultAirSpeed
-    property real _climbRate:           _activeVehicle ? _activeVehicle.climbRate     : _defaultClimbRate
+
+    property Fact _emptyFact:           Fact { }
+    property Fact _groundSpeedFact:     _activeVehicle ? _activeVehicle.groundSpeed   : _emptyFact
+    property Fact _airSpeedFact:        _activeVehicle ? _activeVehicle.airSpeed      : _emptyFact
+    property Fact _altitudeWGS84Fact:   _activeVehicle ? _activeVehicle.altitudeWGS84 : _emptyFact
 
     property bool activeVehicleJoystickEnabled: _activeVehicle ? _activeVehicle.joystickEnabled : false
 

src/FlightDisplay/FlightDisplayViewWidgets.qml

@@ -39,7 +39,8 @@ Item {
 
     readonly property string _InstrumentVisibleKey: "IsInstrumentPanelVisible"
 
-    property bool _isInstrumentVisible: QGroundControl.loadBoolGlobalSetting(_InstrumentVisibleKey, true)
+    property bool   _isInstrumentVisible:   QGroundControl.loadBoolGlobalSetting(_InstrumentVisibleKey, true)
+    property var    _activeVehicle:         multiVehicleManager.activeVehicle
 
     QGCMapPalette { id: mapPal; lightColors: !isBackgroundDark }
 
@@ -101,9 +102,9 @@ Item {
         heading:                _heading
         rollAngle:              _roll
         pitchAngle:             _pitch
-        altitude:               _altitudeWGS84
-        groundSpeed:            _groundSpeed
-        airSpeed:               _airSpeed
+        altitudeFact:           _altitudeWGS84Fact
+        groundSpeedFact:        _groundSpeedFact
+        airSpeedFact:           _airSpeedFact
         isSatellite:            _mainIsMap ? _flightMap ? _flightMap.isSatelliteMap : true : true
         z:                      QGroundControl.zOrderWidgets
         onClicked: {
@@ -127,7 +128,7 @@ Item {
             spacing:            ScreenTools.defaultFontPixelSize * 0.33
             anchors.verticalCenter: parent.verticalCenter
             QGCLabel {
-                text:           "Altitude (m)"
+                text:           _altitudeWGS84Fact.shortDescription + "(" + _altitudeWGS84Fact.units + ")"
                 font.pixelSize: ScreenTools.defaultFontPixelSize * 0.75
                 width:          parent.width
                 height:         ScreenTools.defaultFontPixelSize * 0.75
@@ -135,7 +136,7 @@ Item {
                 horizontalAlignment: TextEdit.AlignHCenter
             }
             QGCLabel {
-                text:           _altitudeWGS84 < 10000 ? _altitudeWGS84.toFixed(1) : _altitudeWGS84.toFixed(0)
+                text:           _altitudeWGS84Fact.valueString
                 font.pixelSize: ScreenTools.defaultFontPixelSize * 1.5
                 font.weight:    Font.DemiBold
                 width:          parent.width
@@ -143,7 +144,7 @@ Item {
                 horizontalAlignment: TextEdit.AlignHCenter
             }
             QGCLabel {
-                text:           "Ground Speed (km/h)"
+                text:           _groundSpeedFact.shortDescription + "(" + _groundSpeedFact.units + ")"
                 font.pixelSize: ScreenTools.defaultFontPixelSize * 0.75
                 width:          parent.width
                 height:         ScreenTools.defaultFontPixelSize * 0.75
@@ -151,7 +152,7 @@ Item {
                 horizontalAlignment: TextEdit.AlignHCenter
             }
             QGCLabel {
-                text:           (_groundSpeed * 3.6).toFixed(1)
+                text:           _groundSpeedFact.valueString
                 font.pixelSize: ScreenTools.defaultFontPixelSize
                 font.weight:    Font.DemiBold
                 width:          parent.width

src/FlightMap/MapItems/VehicleMapItem.qml

@@ -51,7 +51,7 @@ MapQuickItem {
         transform: Rotation {
             origin.x:   vehicleIcon.width  / 2
             origin.y:   vehicleIcon.height / 2
-            angle:      vehicle ? vehicle.heading : 0
+            angle:      vehicle ? vehicle.heading.value : 0
         }
     }
 }

src/FlightMap/Widgets/QGCInstrumentWidget.qml

@@ -29,8 +29,9 @@ This file is part of the QGROUNDCONTROL project
 
 import QtQuick 2.4
 
-import QGroundControl.Controls 1.0
-import QGroundControl.ScreenTools 1.0
+import QGroundControl.Controls      1.0
+import QGroundControl.ScreenTools   1.0
+import QGroundControl.FactSystem    1.0
 
 Item {
     id:     root
@@ -41,13 +42,15 @@ Item {
     property alias  heading:        compass.heading
     property alias  rollAngle:      attitude.rollAngle
     property alias  pitchAngle:     attitude.pitchAngle
-    property real   altitude:       0
-    property real   groundSpeed:    0
-    property real   airSpeed:       0
     property real   size:           _defaultSize
     property bool   isSatellite:    false
     property bool   active:         false
 
+    property Fact   _emptyFact:         Fact { }
+    property Fact   groundSpeedFact:    _emptyFact
+    property Fact   airSpeedFact:       _emptyFact
+    property Fact   altitudeFact:       _emptyFact
+
     property real   _defaultSize:   ScreenTools.defaultFontPixelSize * (9)
 
     property real   _sizeRatio:     ScreenTools.isTinyScreen ? (size / _defaultSize) * 0.5 : size / _defaultSize
@@ -84,7 +87,7 @@ Item {
                 anchors.horizontalCenter: parent.horizontalCenter
             }
             QGCLabel {
-                text:           "Altitude (m)"
+                text:           altitudeFact.shortDescription + " (" + altitudeFact.units + ")"
                 font.pixelSize: _labelFontSize
                 width:          parent.width
                 height:         _labelFontSize
@@ -92,7 +95,7 @@ Item {
                 horizontalAlignment: TextEdit.AlignHCenter
             }
             QGCLabel {
-                text:           altitude < 10000 ? altitude.toFixed(1) : altitude.toFixed(0)
+                text:           altitudeFact.valueString
                 font.pixelSize: _bigFontSize
                 font.weight:    Font.DemiBold
                 width:          parent.width
@@ -105,25 +108,25 @@ Item {
                 width:          parent.width * 0.9
                 color:          isSatellite ? Qt.rgba(0,0,0,0.25) : Qt.rgba(1,1,1,0.25)
                 anchors.horizontalCenter: parent.horizontalCenter
-                visible:        airSpeed <= 0 && !ScreenTools.isTinyScreen
+                visible:        airSpeedFact.value <= 0 && !ScreenTools.isTinyScreen
             }
             QGCLabel {
-                text:           "Ground Speed (km/h)"
+                text:           groundSpeedFact.shortDescription + " (" + groundSpeedFact.units + ")"
                 font.pixelSize: _labelFontSize
                 width:          parent.width
                 height:         _labelFontSize
                 color:          isSatellite ? "black" : "white"
                 horizontalAlignment: TextEdit.AlignHCenter
-                visible:        airSpeed <= 0 && !ScreenTools.isTinyScreen
+                visible:        airSpeedFact.value <= 0 && !ScreenTools.isTinyScreen
             }
             QGCLabel {
-                text:           (groundSpeed * 3.6).toFixed(1)
+                text:           groundSpeedFact.valueString
                 font.pixelSize: _normalFontSize
                 font.weight:    Font.DemiBold
                 width:          parent.width
                 color:          isSatellite ? "black" : "white"
                 horizontalAlignment: TextEdit.AlignHCenter
-                visible:        airSpeed <= 0 && !ScreenTools.isTinyScreen
+                visible:        airSpeedFact.value <= 0 && !ScreenTools.isTinyScreen
             }
             //-- Air Speed