[HDF]hdf-4.2.6类库的使用

　　HDF文件包括科学数据和VData部分。读取HDF格式的calipso数据，用GDAL可以方便的读取其中的子数据集，但是没有发现GDAL中提供读取Vdata的方法。所以只好考虑借助hdf-4.2.6类库本身。毕竟GDAL也是采用的hdf-4.2.6类库进行了一次封装。

首先从HdfGroup网站下载一个编译好的安装包。解压后目录如下：

新建一个Win32控制台项目。

添加包含和引用的lib，注意安装目录文件夹下的lib文件夹中的.lib文件应该是relese版本的，我这里引用了dll文件夹下的.lib文件。

从Hdf4.2.6源码中找到VD_create_onefield_vdatas.c文件。我这里修改为VD_create_onefield_vdatas.cpp，添加到项目中，把项目中的HdfFirst.cpp直接排除掉，因为里面有个Main函数。

同时在VD_create_onefield_vdatas.cpp添加

#include "stdafx.h"

完整代码：

 #include "stdafx.h"
 #include "hdf.h" 

 #define  FILE_NAME      "General_Vdatas.hdf"
 #define  CLASS1_NAME    "5x1 Array"
 #define  CLASS2_NAME    "6x4 Array"
 #define  VDATA1_NAME    "First Vdata"
 #define  VDATA2_NAME    "Second Vdata"
 #define  FIELD1_NAME    "Single-component Field"
 #define  FIELD2_NAME    "Multi-component Field"
 #define  N_RECORDS_1    5    /* number of records the first vdata contains  */
 #define  N_RECORDS_2    6    /* number of records the second vdata contains */
 #define  ORDER_2        4    /* order of the field in the second vdata      */
                 /* Note that the order of the field in the first vdata is 1 */

 int main( )
 {
    /************************* Variable declaration **************************/

    intn  status_n;      /* returned status for functions returning an intn  */
    int32 status_32;     /* returned status for functions returning an int32 */
    int32 file_id, vdata1_ref, vdata2_ref; 

    /*
    * Define an array to buffer the data of the first vdata.
    */
    char8 vdata1_buf [N_RECORDS_1] = {'V', 'D', 'A', 'T', 'A'};

    /*
    * Define an array to buffer the data of the second vdata.
    */
    int32 vdata2_buf [N_RECORDS_2][ORDER_2] = {{, , , }, {, , , },
                                               {, , , }, {, , , },
                                               {, , , }, {, , , }};

    /********************** End of variable declaration **********************/

    /*
    * Open the HDF file for writing.
    */
    file_id = Hopen (FILE_NAME, DFACC_WRITE, );

    /*
    * Initialize the VS interface.
    */
    status_n = Vstart (file_id);

    /*
    * Create the first vdata and populate it with data from the vdata1_buf
    * array. Note that the buffer vdata1_buf is cast to (uint8 *) for the
    * benefit of generic data type.
    */
    vdata1_ref = VHstoredata (file_id, FIELD1_NAME, (uint8 *)vdata1_buf,
                        N_RECORDS_1, DFNT_CHAR8, VDATA1_NAME, CLASS1_NAME); 

    /*
    * Create the second vdata and populate it with data from the vdata2_buf
    * array.
    */
    vdata2_ref = VHstoredatam (file_id, FIELD2_NAME, (uint8 *)vdata2_buf,
                N_RECORDS_2, DFNT_INT32, VDATA2_NAME, CLASS2_NAME, ORDER_2); 

    /*
    * Terminate access to the VS interface and close the HDF file.
    */
    status_n = Vend (file_id);
    status_32 = Hclose (file_id);
    return ;
 }

将Dll文件拷贝到Debug目录下，运行，发现目录下生成了General_Vdatas.hdf文件。在Matlab中查看：