GDALDataset *SDTSDataset::Open( GDALOpenInfo * poOpenInfo )

{
    int         i;
    
/* -------------------------------------------------------------------- */
/*      Before trying SDTSOpen() we first verify that the first         */
/*      record is in fact a SDTS file descriptor record.                */
/* -------------------------------------------------------------------- */
    char        *pachLeader = (char *) poOpenInfo->pabyHeader;
    
    if( poOpenInfo->nHeaderBytes < 24 )
        return NULL;

    if( pachLeader[5] != '1' && pachLeader[5] != '2' && pachLeader[5] != '3' )
        return NULL;

    if( pachLeader[6] != 'L' )
        return NULL;

    if( pachLeader[8] != '1' && pachLeader[8] != ' ' )
        return NULL;

/* -------------------------------------------------------------------- */
/*      Try opening the dataset.                                        */
/* -------------------------------------------------------------------- */
    SDTSTransfer        *poTransfer = new SDTSTransfer;
    
    if( !poTransfer->Open( poOpenInfo->pszFilename ) )
    {
        delete poTransfer;
        return NULL;
    }
    
/* -------------------------------------------------------------------- */
/*      Confirm the requested access is supported.                      */
/* -------------------------------------------------------------------- */
    if( poOpenInfo->eAccess == GA_Update )
    {
        delete poTransfer;
        CPLError( CE_Failure, CPLE_NotSupported, 
                  "The SDTS driver does not support update access to existing"
                  " datasets.\n" );
        return NULL;
    }
    
/* -------------------------------------------------------------------- */
/*      Find the first raster layer.  If there are none, abort          */
/*      returning an error.                                             */
/* -------------------------------------------------------------------- */
    SDTSRasterReader    *poRL = NULL;

    for( i = 0; i < poTransfer->GetLayerCount(); i++ )
    {
        if( poTransfer->GetLayerType( i ) == SLTRaster )
        {
            poRL = poTransfer->GetLayerRasterReader( i );
            break;
        }
    }

    if( poRL == NULL )
    {
        delete poTransfer;
        
        CPLError( CE_Warning, CPLE_AppDefined,
                  "%s is an SDTS transfer, but has no raster cell layers.\n"
                  "Perhaps it is a vector transfer?\n",
                  poOpenInfo->pszFilename );
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Initialize a corresponding GDALDataset.                         */
/* -------------------------------------------------------------------- */
    SDTSDataset *poDS = new SDTSDataset();

    poDS->poTransfer = poTransfer;
    poDS->poRL = poRL;
    
/* -------------------------------------------------------------------- */
/*      Capture some information from the file that is of interest.     */
/* -------------------------------------------------------------------- */
    poDS->nRasterXSize = poRL->GetXSize();
    poDS->nRasterYSize = poRL->GetYSize();
    
/* -------------------------------------------------------------------- */
/*      Create band information objects.                                */
/* -------------------------------------------------------------------- */
    poDS->nBands = 1;
    poDS->papoBands = (GDALRasterBand **)
        VSICalloc(sizeof(GDALRasterBand *),poDS->nBands);

    for( i = 0; i < poDS->nBands; i++ )
        poDS->SetBand( i+1, new SDTSRasterBand( poDS, i+1, poRL ) );

/* -------------------------------------------------------------------- */
/*      Try to establish the projection string.  For now we only        */
/*      support UTM and GEO.                                            */
/* -------------------------------------------------------------------- */
    OGRSpatialReference   oSRS;
    SDTS_XREF   *poXREF = poTransfer->GetXREF();

    if( EQUAL(poXREF->pszSystemName,"UTM") )
    {									
        oSRS.SetUTM( poXREF->nZone );
    }
    else if( EQUAL(poXREF->pszSystemName,"GEO") )
    {
        /* we set datum later */
    }
    else
        oSRS.SetLocalCS( poXREF->pszSystemName );

    if( oSRS.IsLocal() )
        /* don't try to set datum. */;
    else if( EQUAL(poXREF->pszDatum,"NAS") )
        oSRS.SetWellKnownGeogCS( "NAD27" );
    else if( EQUAL(poXREF->pszDatum, "NAX") )
        oSRS.SetWellKnownGeogCS( "NAD83" );
    else if( EQUAL(poXREF->pszDatum, "WGC") )
        oSRS.SetWellKnownGeogCS( "WGS72" );
    else if( EQUAL(poXREF->pszDatum, "WGE") )
        oSRS.SetWellKnownGeogCS( "WGS84" );
    else
        oSRS.SetWellKnownGeogCS( "WGS84" );

    oSRS.Fixup();

    poDS->pszProjection = NULL;
    if( oSRS.exportToWkt( &poDS->pszProjection ) != OGRERR_NONE )
        poDS->pszProjection = CPLStrdup("");


/* -------------------------------------------------------------------- */
/*      Get metadata from the IDEN file.                                */
/* -------------------------------------------------------------------- */
    const char* pszIDENFilePath = poTransfer->GetCATD()->GetModuleFilePath("IDEN");
    if (pszIDENFilePath)
    {
        DDFModule   oIDENFile;
        if( oIDENFile.Open( pszIDENFilePath ) )
        {
            DDFRecord* poRecord;

            while( (poRecord = oIDENFile.ReadRecord()) != NULL )
            {

                if( poRecord->GetStringSubfield( "IDEN", 0, "MODN", 0 ) == NULL )
                    continue;

                static const char* fields[][2] = { { "TITL", "TITLE" },
                                                   { "DAID", "DATASET_ID" },
                                                   { "DAST", "DATA_STRUCTURE" },
                                                   { "MPDT", "MAP_DATE" },
                                                   { "DCDT", "DATASET_CREATION_DATE" } };

                for (i = 0; i < (int)sizeof(fields) / (int)sizeof(fields[0]) ; i++)
                {
                    const char* pszFieldValue =
                            poRecord->GetStringSubfield( "IDEN", 0, fields[i][0], 0 );
                    if ( pszFieldValue )
                        poDS->SetMetadataItem(fields[i][1], pszFieldValue);
                }

                break;
            }
        }
    }

/* -------------------------------------------------------------------- */
/*      Initialize any PAM information.                                 */
/* -------------------------------------------------------------------- */
    poDS->SetDescription( poOpenInfo->pszFilename );
    poDS->TryLoadXML();

    return( poDS );
}
Beispiel #2
0
GDALDataset *BTDataset::Open( GDALOpenInfo * poOpenInfo )

{
/* -------------------------------------------------------------------- */
/*      Verify that this is some form of binterr file.                  */
/* -------------------------------------------------------------------- */
    if( poOpenInfo->nHeaderBytes < 256)
        return NULL;

    if( !STARTS_WITH((const char *) poOpenInfo->pabyHeader, "binterr") )
        return NULL;

/* -------------------------------------------------------------------- */
/*      Create the dataset.                                             */
/* -------------------------------------------------------------------- */
    BTDataset *poDS = new BTDataset();

    memcpy( poDS->abyHeader, poOpenInfo->pabyHeader, 256 );

/* -------------------------------------------------------------------- */
/*      Get the version.                                                */
/* -------------------------------------------------------------------- */
    char szVersion[4] = {};

    strncpy( szVersion, (char *) (poDS->abyHeader + 7), 3 );
    szVersion[3] = '\0';
    poDS->nVersionCode = static_cast<int>(CPLAtof(szVersion) * 10);

/* -------------------------------------------------------------------- */
/*      Extract core header information, being careful about the        */
/*      version.                                                        */
/* -------------------------------------------------------------------- */

    GInt32 nIntTemp = 0;
    memcpy( &nIntTemp, poDS->abyHeader + 10, 4 );
    poDS->nRasterXSize = CPL_LSBWORD32( nIntTemp );

    memcpy( &nIntTemp, poDS->abyHeader + 14, 4 );
    poDS->nRasterYSize = CPL_LSBWORD32( nIntTemp );

    if( !GDALCheckDatasetDimensions(poDS->nRasterXSize, poDS->nRasterYSize) )
    {
        delete poDS;
        return NULL;
    }

    GInt16 nDataSize = 0;
    memcpy( &nDataSize, poDS->abyHeader+18, 2 );
    nDataSize = CPL_LSBWORD16( nDataSize );

    GDALDataType eType = GDT_Unknown;
    if( poDS->abyHeader[20] != 0 && nDataSize == 4 )
        eType = GDT_Float32;
    else if( poDS->abyHeader[20] == 0 && nDataSize == 4 )
        eType = GDT_Int32;
    else if( poDS->abyHeader[20] == 0 && nDataSize == 2 )
        eType = GDT_Int16;
    else
    {
        CPLError( CE_Failure, CPLE_AppDefined,
                  ".bt file data type unknown, got datasize=%d.",
                  nDataSize );
        delete poDS;
        return NULL;
    }

    /*
        rcg, apr 7/06: read offset 62 for vert. units.
        If zero, assume 1.0 as per spec.

    */
    memcpy( &poDS->m_fVscale, poDS->abyHeader + 62, 4 );
    CPL_LSBPTR32(&poDS->m_fVscale);
    if(poDS->m_fVscale == 0.0f)
        poDS->m_fVscale = 1.0f;

/* -------------------------------------------------------------------- */
/*      Try to read a .prj file if it is indicated.                     */
/* -------------------------------------------------------------------- */
    OGRSpatialReference oSRS;

    if( poDS->nVersionCode >= 12 && poDS->abyHeader[60] != 0 )
    {
        const char  *pszPrjFile = CPLResetExtension( poOpenInfo->pszFilename,
                                                     "prj" );
        VSILFILE *fp = VSIFOpenL( pszPrjFile, "rt" );
        if( fp != NULL )
        {
            const int nBufMax = 10000;

            char *pszBuffer = static_cast<char *>(CPLMalloc(nBufMax));
            const int nBytes =
                static_cast<int>(VSIFReadL( pszBuffer, 1, nBufMax-1, fp ));
            CPL_IGNORE_RET_VAL(VSIFCloseL( fp ));

            pszBuffer[nBytes] = '\0';

            char *pszBufPtr = pszBuffer;
            if( oSRS.importFromWkt( &pszBufPtr ) != OGRERR_NONE )
            {
                CPLError( CE_Warning, CPLE_AppDefined,
                          "Unable to parse .prj file, "
                          "coordinate system missing." );
            }
            CPLFree( pszBuffer );
        }
    }

/* -------------------------------------------------------------------- */
/*      If we didn't find a .prj file, try to use internal info.        */
/* -------------------------------------------------------------------- */
    if( oSRS.GetRoot() == NULL )
    {
        GInt16 nUTMZone = 0;
        memcpy( &nUTMZone, poDS->abyHeader + 24, 2 );
        nUTMZone = CPL_LSBWORD16( nUTMZone );

        GInt16 nDatum = 0;
        memcpy( &nDatum, poDS->abyHeader + 26, 2 );
        nDatum = CPL_LSBWORD16( nDatum );

        GInt16 nHUnits = 0;
        memcpy( &nHUnits, poDS->abyHeader + 22, 2 );
        nHUnits = CPL_LSBWORD16( nHUnits );

        if( nUTMZone != 0 )
            oSRS.SetUTM( std::abs(static_cast<int>(nUTMZone)), nUTMZone > 0 );
        else if( nHUnits != 0 )
            oSRS.SetLocalCS( "Unknown" );

        if( nHUnits == 1 )
            oSRS.SetLinearUnits( SRS_UL_METER, 1.0 );
        else if( nHUnits == 2 )
            oSRS.SetLinearUnits( SRS_UL_FOOT, CPLAtof(SRS_UL_FOOT_CONV) );
        else if( nHUnits == 3 )
            oSRS.SetLinearUnits( SRS_UL_US_FOOT, CPLAtof(SRS_UL_US_FOOT_CONV) );

        // Translate some of the more obvious old USGS datum codes
        if( nDatum == 0 )
            nDatum = 6201;
        else if( nDatum == 1 )
            nDatum = 6209;
        else if( nDatum == 2 )
            nDatum = 6210;
        else if( nDatum == 3 )
            nDatum = 6202;
        else if( nDatum == 4 )
            nDatum = 6203;
        else if( nDatum == 6 )
            nDatum = 6222;
        else if( nDatum == 7 )
            nDatum = 6230;
        else if( nDatum == 13 )
            nDatum = 6267;
        else if( nDatum == 14 )
            nDatum = 6269;
        else if( nDatum == 17 )
            nDatum = 6277;
        else if( nDatum == 19 )
            nDatum = 6284;
        else if( nDatum == 21 )
            nDatum = 6301;
        else if( nDatum == 22 )
            nDatum = 6322;
        else if( nDatum == 23 )
            nDatum = 6326;

        if( !oSRS.IsLocal() )
        {
            if( nDatum >= 6000 )
            {
                char szName[32];
                snprintf( szName, sizeof(szName), "EPSG:%d", nDatum-2000 );
                oSRS.SetWellKnownGeogCS( szName );
            }
            else
                oSRS.SetWellKnownGeogCS( "WGS84" );
        }
    }

/* -------------------------------------------------------------------- */
/*      Convert coordinate system back to WKT.                          */
/* -------------------------------------------------------------------- */
    if( oSRS.GetRoot() != NULL )
        oSRS.exportToWkt( &poDS->pszProjection );

/* -------------------------------------------------------------------- */
/*      Get georeferencing bounds.                                      */
/* -------------------------------------------------------------------- */
    if( poDS->nVersionCode >= 11 )
    {
        double dfLeft = 0.0;
        memcpy( &dfLeft, poDS->abyHeader + 28, 8 );
        CPL_LSBPTR64( &dfLeft );

        double dfRight = 0.0;
        memcpy( &dfRight, poDS->abyHeader + 36, 8 );
        CPL_LSBPTR64( &dfRight );

        double dfBottom = 0.0;
        memcpy( &dfBottom, poDS->abyHeader + 44, 8 );
        CPL_LSBPTR64( &dfBottom );

        double dfTop = 0.0;
        memcpy( &dfTop, poDS->abyHeader + 52, 8 );
        CPL_LSBPTR64( &dfTop );

        poDS->adfGeoTransform[0] = dfLeft;
        poDS->adfGeoTransform[1] = (dfRight - dfLeft) / poDS->nRasterXSize;
        poDS->adfGeoTransform[2] = 0.0;
        poDS->adfGeoTransform[3] = dfTop;
        poDS->adfGeoTransform[4] = 0.0;
        poDS->adfGeoTransform[5] = (dfBottom - dfTop) / poDS->nRasterYSize;

        poDS->bGeoTransformValid = TRUE;
    }

/* -------------------------------------------------------------------- */
/*      Re-open the file with the desired access.                       */
/* -------------------------------------------------------------------- */

    if( poOpenInfo->eAccess == GA_Update )
        poDS->fpImage = VSIFOpenL( poOpenInfo->pszFilename, "rb+" );
    else
        poDS->fpImage = VSIFOpenL( poOpenInfo->pszFilename, "rb" );

    if( poDS->fpImage == NULL )
    {
        CPLError( CE_Failure, CPLE_OpenFailed,
                  "Failed to re-open %s within BT driver.\n",
                  poOpenInfo->pszFilename );
        delete poDS;
        return NULL;
    }
    poDS->eAccess = poOpenInfo->eAccess;

/* -------------------------------------------------------------------- */
/*      Create band information objects                                 */
/* -------------------------------------------------------------------- */
    poDS->SetBand( 1, new BTRasterBand( poDS, poDS->fpImage, eType ) );

#ifdef notdef
    poDS->bGeoTransformValid =
        GDALReadWorldFile( poOpenInfo->pszFilename, ".wld",
                           poDS->adfGeoTransform );
#endif

/* -------------------------------------------------------------------- */
/*      Initialize any PAM information.                                 */
/* -------------------------------------------------------------------- */
    poDS->SetDescription( poOpenInfo->pszFilename );
    poDS->TryLoadXML();

/* -------------------------------------------------------------------- */
/*      Check for overviews.                                            */
/* -------------------------------------------------------------------- */
    poDS->oOvManager.Initialize( poDS, poOpenInfo->pszFilename );

    return poDS;
}