shp文件奥秘及c语言编程对策,VS2017编译GDAL(64bit)+解决C#读取Shp数据中文路径的问题...

编译GDAL过程比较繁琐&＃xff0c;查阅了网上相关资料&＃xff0c;同时通过实践&＃xff0c;完成GDAL的编译&＃xff0c;同时解决了SHP数据中文路径及中文字段乱码的问题&＃xff0c;本文以“gdal-2.3.2”版本为例阐述整个编译过程。

一、编译准备

1、编译工具是VS2017&＃xff0c;编译前需要下载“gdal-2.3.2”和“swigwin-3.0.12”&＃xff0c;下载链接如下&＃xff1a;

GDAL&＃xff1a;http://trac.osgeo.org/gdal/wiki/DownloadSource

swigwin&＃xff1a;https://sourceforge.net/projects/swig/files/swigwin/

2、在“D盘”新建目录“GDAL”&＃xff0c;将两个压缩包解压到该目录中&＃xff0c;同时新建一个文件夹用于存放编译结果(如“D:\GDAL\GDAL\GDAL232“”)&＃xff0c;如图所示&＃xff1a;

3、修改“D:\GDAL\gdal-2.3.2\nmake.opt”文件&＃xff0c;如下图&＃xff1a;

文件“nmake.opt”修改如下&＃xff1a;

修改57行&＃xff0c;GDAL_HOME &＃61; "D:\GDAL\GDAL\GDAL232"(编译后文件的生成目录)

修改86行&＃xff0c;SWIG &＃61; D:\GDAL\swigwin-3.0.12\swig.exe(这个必须是完全路径)

修改184行&＃xff0c;去掉“#”&＃xff0c;效果为WIN64&＃61;YES

修改960行&＃xff0c;去掉后边的下划线&＃xff0c;效果为SYM_PREFIX&＃61;

二、编译C&＃43;&＃43;

以管理员运行【开始】-【所有程序】-【Visual Studio 2017】-【Visual Studio Tools】-【VC】-【适用于 VS 2017 的 x64 本机工具命令提示】菜单&＃xff0c;弹出命令框如图所示&＃xff1a;

输入cd D:\GDAL\gdal-2.3.2 切换至gdal-2.3.2目录&＃xff0c;如图所示&＃xff1a;

然后依次输入&＃xff1a;

nmake /f makefile.vc

nmake /f makefile.vc install

nmake /f makefile.vc devinstall

C&＃43;&＃43;编译时间较长&＃xff0c;需要耐心等待……

三、编译C#

1、修改C#源码文件

打开“D:\GDAL\gdal-2.3.2\swig\csharp\AssemblyInfo.cs”&＃xff0c;注释掉【[assembly: AllowPartiallyTrustedCallers]】&＃xff0c;如下图所示&＃xff1a;

打开如下三个文件&＃xff1a;

“D:\GDAL\gdal-2.3.2\swig\csharp\gdal\GdalPINVOKE.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\ogr\OgrPINVOKE.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\osr\OsrPINVOKE.cs”

分别注释掉重复的构造函数&＃xff0c;如图所示&＃xff1a;

打开如下三个文件&＃xff1a;

“D:\GDAL\gdal-2.3.2\swig\csharp\gdal\Band.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\gdal\Dataset.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\gdal\Driver.cs”

文件&＃xff0c;修改接口成员(大概17行)&＃xff0c;如下&＃xff1a;

public Band(IntPtr cPtr, bool cMemoryOwn, object parent): base(GdalPINVOKE.Band_SWIGUpcast(cPtr), cMemoryOwn, parent){swigCPtr &＃61; new HandleRef(this, cPtr);}public Dataset(IntPtr cPtr, bool cMemoryOwn, object parent): base(GdalPINVOKE.Band_SWIGUpcast(cPtr), cMemoryOwn, parent){swigCPtr &＃61; new HandleRef(this, cPtr);}public Driver(IntPtr cPtr, bool cMemoryOwn, object parent): base(GdalPINVOKE.Band_SWIGUpcast(cPtr), cMemoryOwn, parent){swigCPtr &＃61; new HandleRef(this, cPtr);}

接下来解决读取中文路径及属性乱码 &＃xff1a;

打开如下四个文件&＃xff1a;

“D:\GDAL\gdal-2.3.2\swig\csharp\const\GdalConstPINVOKE.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\gdal\GdalPINVOKE.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\ogr\OgrPINVOKE.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\osr\OsrPINVOKE.cs”

分别修改类“SWIGStringHelper”(大概168行)&＃xff0c;具体代码(红色为修改过得代码)如下&＃xff1a;

protected classSWIGStringHelper {public delegate stringSWIGStringDelegate(IntPtr message);static SWIGStringDelegate stringDelegate &＃61; newSWIGStringDelegate(CreateString);

[global::System.Runtime.InteropServices.DllImport("ogr_wrap", EntryPoint&＃61;"SWIGRegisterStringCallback_Ogr")]public static extern voidSWIGRegisterStringCallback_Ogr(SWIGStringDelegate stringDelegate);static stringCreateString(IntPtr pNativeData)

{if (pNativeData &＃61;&＃61;IntPtr.Zero)return "";int i &＃61; 0;byte[] strbuf1 &＃61; new byte[1];

Marshal.Copy(pNativeData&＃43; i, strbuf1, 0, 1);while (strbuf1[0] !&＃61; 0)

{

i&＃43;&＃43;;

strbuf1&＃61; new byte[1];

Marshal.Copy(pNativeData&＃43; i, strbuf1, 0, 1);

}int length &＃61; i;//循环查找字符串的长度

byte[] strbuf &＃61; new byte[length];

Marshal.Copy(pNativeData, strbuf,0, length);returnSystem.Text.Encoding.UTF8.GetString(strbuf);

}staticSWIGStringHelper() {

SWIGRegisterStringCallback_Ogr(stringDelegate);

}

}

打开如下三个文件&＃xff1a;

“D:\GDAL\gdal-2.3.2\swig\csharp\gdal\Gdal.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\ogr\Ogr.cs”

“D:\GDAL\gdal-2.3.2\swig\csharp\osr\Osr.cs”

分别修改函数“Utf8BytesToString”&＃xff0c;代码如下&＃xff1a;

internal static stringUtf8BytesToString(IntPtr pNativeData)

{if (pNativeData &＃61;&＃61;IntPtr.Zero)return null;int i &＃61; 0;byte[] strbuf1 &＃61; new byte[1];

Marshal.Copy(pNativeData&＃43; i, strbuf1, 0, 1);while (strbuf1[0] !&＃61; 0)

{

i&＃43;&＃43;;

strbuf1&＃61; new byte[1];

Marshal.Copy(pNativeData&＃43; i, strbuf1, 0, 1);

}int length &＃61; i;//循环查找字符串的长度

byte[] strbuf &＃61; new byte[length];

Marshal.Copy(pNativeData, strbuf,0, length);//int length &＃61; Marshal.PtrToStringAnsi(pNativeData).Length;//byte[] strbuf &＃61; new byte[length];//Marshal.Copy(pNativeData, strbuf, 0, length);

returnSystem.Text.Encoding.UTF8.GetString(strbuf);

}

2、编译

输入cd swig\csharp &＃xff0c;切换到csharp目录&＃xff0c;

输入nmake /f makefile.vc(运行这一步有问题的话&＃xff0c;加以下两句&＃xff1a;namke /f makefile.vc clear 、nmake /f makefile.vc interface)

输入nmake /f makefile.vc install

编译完成后&＃xff0c;在目录“D:\GDAL\GDAL\GDAL232\csharp”会生成8个文件&＃xff0c;如图所示&＃xff1a;

注&＃xff1a;C#编译过程中&＃xff0c;如果出现HandleRef和IntPtr没有引用的错误&＃xff0c;只需要在相应文件中添加命名空间

using System;

using System.Runtime.InteropServices;即可解决该问题

四、测试DLL

新建一个Winform应用程序&＃xff0c;修改运行配置为x64&＃xff0c;如图所示&＃xff1a;

把“D:\GDAL\GDAL\GDAL232\csharp”中的8个dll和“D:\GDAL\GDAL\GDAL232\bin”中的一个dll复制到“x64/Release”目录下&＃xff0c;添加引用

读取Shp数据的代码如下&＃xff1a;

OSGeo.GDAL.Gdal.AllRegister();

OSGeo.OGR.Ogr.RegisterAll();

OSGeo.OGR.Driver dr&＃61; OSGeo.OGR.Ogr.GetDriverByName("ESRI shapefile");

OSGeo.OGR.DataSource ds&＃61; dr.Open(path, 0);if (ds &＃61;&＃61; null)

{

MessageBox.Show("文件不能打开&＃xff0c;请检查&＃xff01;");return;

}

效果如图所示&＃xff1a;