用GDAL/OGR去讀shapefile

一、讀shapefile

1、首先，用Arcgis創建所要讀的shp文件。打開ArcCatalog,右鍵NEW->Shapefile，名稱Name:point ，要素類型（Feature Type）:Point。點擊Edit，選擇投影類型。

2、打開ArcMap. 單擊工具欄里的Add data按鈕，打開剛才創建的point.shp文件。

3、添加5個點要素，並添加字段（添加字段要在非編輯模式下，修改字段的值要在編輯模式下，記得退出編輯時要保存），如圖所示：

編輯如下C++/GDAL代碼：

 

#include "ogrsf_frmts.h"

int main()

{
	OGRRegisterAll();

	OGRDataSource *poDS;

	poDS = OGRSFDriverRegistrar::Open( "G:\\LJF\\point.shp", FALSE );//shape文件存放的路徑（point.shp即為自己創建的文件）
	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 )//獲得要素，本實例指的是五個點，所以會循環5次
	{
		OGRFeatureDefn *poFDefn = poLayer->GetLayerDefn();
		int iField;
		int i=poFDefn->GetFieldCount(); //獲得字段的數目，本實例返回5，不包括前兩個字段（FID,Shape），這兩個字段在arcgis里也不能被修改;
		for( iField = 0; iField < poFDefn->GetFieldCount(); iField++ )
		{
			OGRFieldDefn *poFieldDefn = poFDefn->GetFieldDefn( iField );
           //根據字段值得類型，選擇對應的輸出
			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;
}

運行結果如下圖：