Q: How can I fix the GPS altitude display?

Platform Development
4

In /usr/share/harbour-gpsinfo/qml/pages/ I could now make a second slider, copying and modifying the one for Update Interval. Starting from line 137:

            Label {
                anchors.left: parent.left
                anchors.leftMargin: Theme.paddingMedium * 2
                text: qsTr("Update interval")
            }

            Slider {
                minimumValue: 1
                maximumValue: 120
                stepSize: 1
                value: settings.updateInterval
                valueText: value + "s"
                width: parent.width
                onReleased: settings.updateInterval = value
            }

            Label {
                anchors.left: parent.left
                anchors.leftMargin: Theme.paddingMedium * 2
                text: qsTr("Altitude Offset")
            }

            Slider {
                minimumValue: -100
                maximumValue: 100
                stepSize: 1
                value: settings.altitudeOffset
                valueText: value + "m"
                width: parent.width
                onReleased: settings.altitudeOffset = value
            }

This works, now the slider occurs in the settings page between the Update Interval slider and the Magnetic Declination input field. The lines in my post #3 looks now this way:

//                            return locationFormatter.roundToDecimal(providers.position.position.coordinate.altitude, 2) + " m"
                            return locationFormatter.roundToDecimal(providers.position.position.coordinate.altitude - settings.altitudeOffset, 2) + " m"
                        } else {
//                            return locationFormatter.roundToDecimal(providers.position.position.coordinate.altitude * 3.2808399, 2) + " ft"
                            return locationFormatter.roundToDecimal((providers.position.position.coordinate.altitude - settings.altitudeOffset) * 3.2808399, 2) + " ft"

It works if a value is set manually after going to the settings page and setting some value, but GPSInfo doesn’t store the setting made here. After each app start it has to be set new. If not, the Altitude shows ‘NaN m’.

What can I do that the app remembers the setting at next app start? What can I do to have a default value of 0 if nothing is set by user?

Thanks for any help!