它可以在Qt c上使用地理位置(国家,州,城市,街道等等)获取地理位置的坐标(纬度和经度).

我知道库QGeoCoordinates,QGeoLocation和QGeoAddress,但我不知道是否可以通过它们从地址获取坐标.

欢迎各方面的帮助.

解决方法:

我需要一些时间来掌握这个,但最后我得到了它的工作.

起初我尝试了你提到的课程：QGeoAddress,QGeoLocation,QGeoCoordinate：

// standard C++ header:
#include <iostream>

// Qt header:
#include <QGeoAddress>
#include <QGeoCoordinate>
#include <QGeoLocation>

using namespace std;

int main()
{
  // build address
  QGeoAddress qGeoAddr;
  qGeoAddr.setCountry(QString::fromUtf8("Germany"));
  qGeoAddr.setPostalCode(QString::fromUtf8("88250"));
  qGeoAddr.setCity(QString::fromUtf8("Weingarten"));
  qGeoAddr.setStreet(QString::fromUtf8("Heinrich-Hertz-Str. 6"));
  QGeoLocation qGeoLoc.setAddress(qGeoAddr);
  QGeoCoordinate qGeoCoord = qGeoLoc.coordinate();
  cout
    << "Lat.:  " << qGeoCoord.latitude() << endl
    << "Long.: " << qGeoCoord.longitude() << endl
    << "Alt.:  " << qGeoCoord.altitude() << endl;
  return 0;
}

这编译并运行,但输出不是很享受：

$./testQGeoAddress
Qt Version: 5.6.2
Lat.:  nan
Long.: nan
Alt.:  nan

那么,代码有什么问题？回过头来思考一下这个我得到了一个线索：有一些服务缺失,可以将地址转换为坐标.这可能是什么？ maps.google.com或类似的东西？

我用Google搜索了一段时间,最后找到了关于Qt位置库的点击.经过实验和摆弄一段时间后,我终于得到了这个运行的例子：

文件testQGeoAddress.pro：

SOURCES = testQGeoAddress.cc

QT += widgets
QT += positioning
QT += location

文件testQGeoAddress.cc：

// standard C++ header:
#include <iostream>
#include <string>

// Qt header:
#include <QApplication>
#include <QGeoAddress>
#include <QGeoCodingManager>
#include <QGeoCoordinate>
#include <QGeoLocation>
#include <QGeoServiceProvider>

using namespace std;

int main(int argc, char **argv)
{
  cout << "Qt Version: " << QT_VERSION_STR << endl;
  // main application
#undef qApp // undef macro qApp out of the way
  QCoreApplication qApp(argc, argv);
  // check for available services
  QStringList qGeoSrvList
    = QGeoServiceProvider::availableServiceProviders();
  for (QString entry : qGeoSrvList) {
    cout << "Try service: " << entry.toStdString() << endl;
    // choose provider
    QGeoServiceProvider qGeoService(entry);
    QGeoCodingManager *pQGeoCoder = qGeoService.geocodingManager();
    if (!pQGeoCoder) {
      cerr
        << "GeoCodingManager '" << entry.toStdString()
        << "' not available!" << endl;
      continue;
    }
    QLocale qLocaleC(QLocale::C, QLocale::AnyCountry);
    pQGeoCoder->setLocale(qLocaleC);
    // build address
    QGeoAddress qGeoAddr;
    qGeoAddr.setCountry(QString::fromUtf8("Germany"));
    qGeoAddr.setPostalCode(QString::fromUtf8("88250"));
    qGeoAddr.setCity(QString::fromUtf8("Weingarten"));
    qGeoAddr.setStreet(QString::fromUtf8("Heinrich-Hertz-Str. 6"));
    QGeoCodeReply *pQGeoCode = pQGeoCoder->geocode(qGeoAddr);
    if (!pQGeoCode) {
      cerr << "GeoCoding totally failed!" << endl;
      continue;
    }
    cout << "Searching..." << endl;
    QObject::connect(pQGeoCode, &QGeoCodeReply::finished,
      [&qApp, &qGeoAddr, pQGeoCode](){
        cout << "Reply: " << pQGeoCode->errorString().toStdString() << endl;
        switch (pQGeoCode->error()) {
#define CASE(ERROR) \
case QGeoCodeReply::ERROR: cerr << #ERROR << endl; break
          CASE(NoError);
          CASE(EngineNotSetError);
          CASE(CommunicationError);
          CASE(ParseError);
          CASE(UnsupportedOptionError);
          CASE(CombinationError);
          CASE(UnknownError);
#undef CASE
          default: cerr << "Undocumented error!" << endl;
        }
        if (pQGeoCode->error() != QGeoCodeReply::NoError) return;
        // eval. result
        QList<QGeoLocation> qGeoLocs = pQGeoCode->locations();
        cout << qGeoLocs.size() << " location(s) returned." << endl;
        for (QGeoLocation &qGeoLoc : qGeoLocs) {
          qGeoLoc.setAddress(qGeoAddr);
          QGeoCoordinate qGeoCoord = qGeoLoc.coordinate();
          cout
            << "Lat.:  " << qGeoCoord.latitude() << endl
            << "Long.: " << qGeoCoord.longitude() << endl
            << "Alt.:  " << qGeoCoord.altitude() << endl;
        }
        qApp.exit(0);
      });
    return qApp.exec();
  }
  return 0;
}

在Windows 10(64位)上使用gg在cygwin中构建：

$qmake-qt5 

$make
g++ -c -pipe -fno-keep-inline-dllexport -O2 -std=gnu++11 -Wall -W -D_REENTRANT -fexceptions -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DQT_LOCATION_LIB -DQT_QUICK_LIB -DQT_GUI_LIB -DQT_POSITIONING_LIB -DQT_QML_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -I. -I/usr/include/qt5 -I/usr/include/qt5/QtWidgets -I/usr/include/qt5/QtLocation -I/usr/include/qt5/QtQuick -I/usr/include/qt5/QtGui -I/usr/include/qt5/QtPositioning -I/usr/include/qt5/QtQml -I/usr/include/qt5/QtNetwork -I/usr/include/qt5/QtCore -I. -I/usr/lib/qt5/mkspecs/cygwin-g++ -o testQGeoAddress.o testQGeoAddress.cc
g++  -o testQGeoAddress.exe testQGeoAddress.o   -lQt5Widgets -lQt5Location -lQt5Quick -lQt5Gui -lQt5Positioning -lQt5Qml -lQt5Network -lQt5Core -lGL -lpthread 

$./testQGeoAddress.exe
Qt Version: 5.6.2
Try service: mapbox
GeoCodingManager 'mapbox' not available!
Try service: osm
Searching...
Reply: 
NoError
1 location(s) returned.
Lat.:  47.8198
Long.: 9.63105
Alt.:  nan

$

第一次尝试不错.关于QGeoCoordinate :: altitude()值：这可能无法从Open Street Map(osm)获得.

要检查结果是否正确,我在maps.google.com中解析了输出坐标：

红色气球是搜索的结果.我在GIMP中添加了蓝点来表达正确的位置.那么,搜索接近正确的位置.差异可能是由于坐标精度有限……