c++qtqtcoreqfileqxmlstreamreader

How to read GPX file ( xml format) in QT?


I have a gpx file , basically that is a xml file. I want to read latitude and longitude values from that. Below i have posted the sample gpx file.

    <gpx>
    <wpt lon="80.0124" lat="13.125">
    </wpt>
    <wpt lon="80.0130" lat="13.124">
    </wpt>
    <wpt lon="80.0145" lat="13.122">
    </wpt>
    <wpt lon="80.0120" lat="13.121">
    </wpt>
    </gpx>

I need to get float values of latitude and longitude. Any help and suggestion is appreciated.

Thank you. Could i get the result without double quotes?


Solution

  • The key class here is QXmlStreamReader.

    See the code below to get it work.

    test.xml

    <gpx>
    <wpt lon="80.0124" lat="13.125">
    </wpt>
    <wpt lon="80.0130" lat="13.124">
    </wpt>
    <wpt lon="80.0145" lat="13.122">
    </wpt>
    <wpt lon="80.0120" lat="13.121">
    </wpt>
    </gpx>
    

    main.cpp

    #include <QXmlStreamReader>
    #include <QDebug>
    #include <QString>
    #include <QFile>
    
    int main()
    {
        QFile file("test.xml");
        if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
            qDebug() << "File open error:" << file.errorString();
            return 1;
        }
        QXmlStreamReader inputStream(&file);
        while (!inputStream.atEnd() && !inputStream.hasError())
        {
            inputStream.readNext();
            if (inputStream.isStartElement()) {
                QString name = inputStream.name().toString();
                if (name == "wpt")
                    qDebug() << "lon:" << inputStream.attributes().value("lon").toFloat() << "lat:" << inputStream.attributes().value("lat").toFloat();
            }
        }
        return 0;
    }
    

    main.pro

    TEMPLATE = app
    TARGET = main
    QT = core
    SOURCES += main.cpp
    

    Build and Run

    qmake && make && ./main
    

    Output

    lon: 80.0124 lat: 13.125 
    lon: 80.013 lat: 13.124 
    lon: 80.0145 lat: 13.122 
    lon: 80.012 lat: 13.121