用GDAL/OGR去读shapefile

一、读shapefile

1、首先，用Arcgis创建所要读的shp文件。打开ArcCatalog,右键NEW->Shapefile，名称Name:point ，要素类型（Feature Type）:Point。点击Edit，选择投影类型。

2、打开ArcMap. 单击工具栏里的Add data按钮，打开刚才创建的point.shp文件。

3、添加5个点要素，并添加字段（添加字段要在非编辑模式下，修改字段的值要在编辑模式下，记得退出编辑时要保存），如图所示：

编辑如下C++/GDAL代码：

#include "ogrsf_frmts.h"

int main()

{

	OGRRegisterAll();

	OGRDataSource *poDS;

	poDS = OGRSFDriverRegistrar::Open( "G:\\LJF\\point.shp", FALSE );//shape文件存放的路径（point.shp即为自己创建的文件）

	if( poDS == NULL )

	{

		printf( "Open failed.\n%s" );

		exit( 1 );

	}

	OGRLayer  *poLayer;

	poLayer = poDS->GetLayerByName( "point" );

	OGRFeature *poFeature;

	poLayer->ResetReading();

	while( (poFeature = poLayer->GetNextFeature()) != NULL )//获得要素，本实例指的是五个点，所以会循环5次

	{

		OGRFeatureDefn *poFDefn = poLayer->GetLayerDefn();

		int iField;

		int i=poFDefn->GetFieldCount(); //获得字段的数目，本实例返回5，不包括前两个字段（FID,Shape），这两个字段在arcgis里也不能被修改;

		for( iField = 0; iField < poFDefn->GetFieldCount(); iField++ )

		{

			OGRFieldDefn *poFieldDefn = poFDefn->GetFieldDefn( iField );

           //根据字段值得类型，选择对应的输出

			if( poFieldDefn->GetType() == OFTInteger )

				printf( "%d,", poFeature->GetFieldAsInteger( iField ) );

			else if( poFieldDefn->GetType() == OFTReal )

				printf( "%.3f,", poFeature->GetFieldAsDouble(iField) );

			else if( poFieldDefn->GetType() == OFTString )

				printf( "%s,", poFeature->GetFieldAsString(iField) );

			else

				printf( "%s,", poFeature->GetFieldAsString(iField) );

		}

		OGRGeometry *poGeometry;

		poGeometry = poFeature->GetGeometryRef();

		if( poGeometry != NULL

			&& wkbFlatten(poGeometry->getGeometryType()) == wkbPoint )

		{

			OGRPoint *poPoint = (OGRPoint *) poGeometry;

			printf( "%.3f,%3.f\n", poPoint->getX(), poPoint->getY() );

		}

		else

		{

			printf( "no point geometry\n" );

		}

		OGRFeature::DestroyFeature( poFeature );

	}

	OGRDataSource::DestroyDataSource( poDS );

	system("pause");

	return 0;

}

运行结果如下图：