GDAL_DATA环境变量的设置

GDAL库在使用时又很多环境变量要提前设置，如果忽略这一步，代码会出现异常失败。本文由描述了静态和运行时两种设置方法供参考。

源码是OGR站点的示例改了一点点，如下。出错部分是红色加粗句，err一直为6。

 

#include "stdafx.h"

#include "cpl_conv.h"

#include <ogr_spatialref.h>

 

bool DoTransForm(int nCS1,int nCS2)

{

    OGRSpatialReference oSourceSRS, oTargetSRS;

    OGRCoordinateTransformation *poCT;

    double x1, y1, x2, y2;

    

    //设置环境变量

    //CPLSetConfigOption( "GDAL_DATA", "d://gdal//data" );

 

    OGRErr err = oSourceSRS.importFromEPSG( nCS1 );

    oTargetSRS.importFromEPSG( nCS2 );

    char *pszWKT = NULL;

    

    //测试

    oSourceSRS.exportToWkt(&pszWKT);

    AfxMessageBox(CString(pszWKT));

 

    //定义转化

    poCT = OGRCreateCoordinateTransformation( &oSourceSRS,&oTargetSRS );

    //x = atof( papszArgv[i+3] );

    //y = atof( papszArgv[i+4] );

    x1 = 100;y1 = 40;

    x2 = x1; y2 = y1;

    char msg[100];

 

    if( poCT == NULL || !poCT->Transform( 1, &x2, &y2 ) )

        AfxMessageBox((CString)("Transformation failed./n" ));

    else

    {

        sprintf(msg, "(%f,%f) -> (%f,%f)/n",x1, y1, x2, y2 );

        AfxMessageBox((CString)msg);

    }

 

    return true;

}

静态设置：我的电脑|属性|高级|环境变量|新建|GDAL_DATA="$GDAL/data"

运行时设置：再调用GDAL库开始处加CPLSetConfigOption( "GDAL_DATA", "d://gdal//data" );