GIS:GDAL开发库

一.GDAL安装

从GDAL 2.0+版本升级到3.0+版本

3.0+版本必须依赖PROJ库，而且PROJ库必须是6.0+版本
PROJ库需要proj.db数据库支持空间参考，默认在proj.dll目录中，也可以通过OSRSetPROJSearchPaths()来设置目录

二.GDAL使用

从GDAL 2.版本升级到3.版本，使用接口发生了改变

OGRSpatialReference类用于实现OpenGIS空间参考系统定义，目前已经支持本地坐标系 地理坐标系 投影坐标系 垂直坐标系 地心坐标系 复合坐标系
OGRSpatialReference::IsProjected()
OGRSpatialReference::IsGeographic()
OGRSpatialReference::GetSemiMajor()
OGRSpatialReference::GetSemiMinor()
OGRSpatialReference::GetInvFlattening()
OGRSpatialReference::GetAttrValue()
OGRSpatialReference::GetProjParm()
OGRSpatialReference::GetLinearUnits()

OGRCoordinateTransform类使用PROJ.4库实现坐标转换
OGRCoordinateTransform::Transform()

//GDAL2.0+版本

void TestLongLat2UTM()
{
  OGRCoordinateTransformation* poCT = nullptr;
  double dfCenterLong = 104.49242396000000;
  double dfCenterLat = 26.311051110000001;
  int nZone = static_cast<int>(dfCenterLong / 6 + 31);
  int bNorth = dfCenterLat >= 0 ? TRUE : FALSE;
  
  OGRSpatialReference oWGS84;
  oWGS84.SetWellKnownGeogCS("WGS84");

  OGRSpatialReference oUtmSrs;
  oUtmSrs.SetWellKnownGeogCS("WGS84");
  oUtmSrs.SetUTM(nZone, bNorth);

  poCT = OGRCreateCoordinateTransformation(&oWGS84, &oUtmSrs);

  double dx = 104.28982973166080;
  double dy = 26.567797593704370;
  double dz = 1826.8254084027094;
  int bTransformSuccess;
  poCT->Transform(1, &dx, &dy, &dz, &bTransformSuccess);

  OGRCoordinateTransformation::DestoryCT(poCT);

}

//GDAL3.0+

void TestLongLat2UTM()
{
  OGRCoordinateTransformation* poCT = nullptr;
  double dfCenterLong = 104.49242396000000;
  double dfCenterLat = 26.311051110000001;
  int nZone = static_cast<int>(dfCenterLong / 6 + 31);
  int bNorth = dfCenterLat >= 0 ? TRUE : FALSE;

  OGRSpatialReference oWGS84;
  oWGS84.SetWellKnownGeogCS("WGS84");
  oWGS84.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);　　//在新版GDAL中，这一行非常重要，必须出现才能运行
  
  OGRSpatialReference oUtmSrs;
  oUtmSrs.SetWellKnownGeogCS("WGS84");
  oUtmSrs.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
  oUtmSrs.SetUTM(nZone, bNorth);

  poCT = OGRCreateCoordinateTransformation(&oWGS84, &oUtmSrs);
  
  double dx = 104.28982973166080;
  double dy = 26.567797593704370;
  double dz = 1826.8254084027094;
  int bTransformSuccess;
  poCT->Transform(1, &dx, &dy, &dz, &bTransformSuccess);

  OGRCoordinateTransformation::DestoryCT(poCT)

}

1.栅格

2.矢量

3.地理网络模型

4.投影和空间参考系统（OSR-OGRSpatialReference）

OGRSpatialReference类

OGRCoordinateTransformation类