[gdal-dev] Help on creating polygon shapefile

[Limei Ran]

Hi:

I am new in using OGR.  I tried to create a polygon shapefile using the 
following codes:

===============
.......
OGRPolygon *poG = new OGRPolygon();
        printf ("Declared OGRPolygon.\n");

        char mesg[256];
        unsigned char *geom;
        sprintf(mesg, 
"POLYGON(%f,%f,%f,%f,%f,%f,%f,%f,%f,%f)\0",x1,y1,x2,y2,x3,y3,x4,y4,x1,y1);
        geom = (unsigned char *) mesg;
        printf("POLYGON: %s\n",geom);

        printf ("Import Wkb.\n");

        if ( poG->importFromWkb(geom,0) != OGRERR_NONE )
        {
           printf( "Importing a Wkb polygon failed.\n" );
           exit( 1 );
        }
.......
==============

But,  poG->importFromWkb failed.  Could you tell me what is wrong with 
the codes?  Is Wkb POLYGON wrong?  I tried to find some sample codes 
and could not find them?  Should I use OGRPolygon::addRingDirectly 
function instead?

Thanks,

Limei