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:

 

转载自:https://blog.csdn.net/q_l_s/article/details/52516704

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