用GDAL/OGR去读shapefile
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用GDAL/OGR去读shapefile
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一、讀shapefile
1、首先,用Arcgis創(chuàng)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(chuàng)建的point.shp文件。
3、添加5個點要素,并添加字段(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:
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#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(chuàng)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(huán)5次{OGRFeatureDefn *poFDefn = poLayer->GetLayerDefn();int iField;int i=poFDefn->GetFieldCount(); //獲得字段的數(shù)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(jù)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) );elseprintf( "%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(jié)果如下圖:
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