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.
%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
", poPoint->getX(), poPoint->getY() );
		}
		else
		{
			printf( "no point geometry
" );
		}       
		OGRFeature::DestroyFeature( poFeature );
	}

	OGRDataSource::DestroyDataSource( poDS );
	system("pause");
	return 0;
}

运行结果如下图：