ntf_raster.cpp

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

        {
            pafElev[iPixel] = (float) (dfVOffset + dfVScale *
                atoi(poRecord->GetField(84+iPixel*4,87+iPixel*4)));
        }
    }
            
/* -------------------------------------------------------------------- */
/*      Handle PROFILE                                                  */
/* -------------------------------------------------------------------- */
    else if( pafElev != NULL && GetProductId() == NPC_LANDFORM_PROFILE_DTM )
    {
        for( int iPixel = 0; iPixel < nRasterXSize; iPixel++ )
        {
            pafElev[iPixel] = (float) 
           (atoi(poRecord->GetField(19+iPixel*5,23+iPixel*5)) * GetZMult());
        }
    }
    
    delete poRecord;

    return CE_None;
}

/************************************************************************/
/* ==================================================================== */
/*                        OGRNTFRasterLayer                             */
/* ==================================================================== */
/************************************************************************/

/************************************************************************/
/*                          OGRNTFRasterLayer                           */
/************************************************************************/

OGRNTFRasterLayer::OGRNTFRasterLayer( OGRNTFDataSource *poDSIn,
                                      NTFFileReader * poReaderIn )

{
    char        szLayerName[128];

    sprintf( szLayerName, "DTM_%s", poReaderIn->GetTileName() );
    poFeatureDefn = new OGRFeatureDefn( szLayerName );
    poFeatureDefn->SetGeomType( wkbPoint25D );

    OGRFieldDefn      oHeight( "HEIGHT", OFTInteger );
    oHeight.SetWidth(5);
    poFeatureDefn->AddFieldDefn( &oHeight );

    poReader = poReaderIn;
    poDS = poDSIn;
    poFilterGeom = NULL;

    pafColumn = (float *) CPLCalloc(sizeof(float),
                                    poReader->GetRasterYSize());
    iColumnOffset = -1;
    iCurrentFC = 0;

/* -------------------------------------------------------------------- */
/*      Check for DEM subsampling, and compute total feature count      */
/*      accordingly.                                                    */
/* -------------------------------------------------------------------- */
    if( poDS->GetOption( "DEM_SAMPLE" ) == NULL )
        nDEMSample = 1;
    else
        nDEMSample = MAX(1,atoi(poDS->GetOption("DEM_SAMPLE")));
    
    nFeatureCount = (poReader->GetRasterXSize() / nDEMSample)
                  * (poReader->GetRasterYSize() / nDEMSample);
}

/************************************************************************/
/*                         ~OGRNTFRasterLayer()                         */
/************************************************************************/

OGRNTFRasterLayer::~OGRNTFRasterLayer()

{
    delete poFeatureDefn;

    if( poFilterGeom != NULL )
        delete poFilterGeom;
}

/************************************************************************/
/*                          SetSpatialFilter()                          */
/************************************************************************/

void OGRNTFRasterLayer::SetSpatialFilter( OGRGeometry * poGeomIn )

{
    if( poFilterGeom != NULL )
    {
        delete poFilterGeom;
        poFilterGeom = NULL;
    }

    if( poGeomIn != NULL )
        poFilterGeom = poGeomIn->clone();
}

/************************************************************************/
/*                            ResetReading()                            */
/************************************************************************/

void OGRNTFRasterLayer::ResetReading()

{
    iCurrentFC = 0;
}

/************************************************************************/
/*                           GetNextFeature()                           */
/************************************************************************/

OGRFeature *OGRNTFRasterLayer::GetNextFeature()

{
    if( iCurrentFC == 0 )
        iCurrentFC = 1;
    else
    {
        int     iReqColumn, iReqRow;
        
        iReqColumn = (iCurrentFC - 1) / poReader->GetRasterYSize();
        iReqRow = iCurrentFC - iReqColumn * poReader->GetRasterXSize() - 1;

        if( iReqRow + nDEMSample > poReader->GetRasterYSize() )
        {
            iReqRow = 0;
            iReqColumn += nDEMSample;
        }
        else
        {
            iReqRow += nDEMSample;
        }

        iCurrentFC = iReqColumn * poReader->GetRasterYSize()
            + iReqRow + 1;
    }

    return GetFeature( (long) iCurrentFC );
}

/************************************************************************/
/*                             GetFeature()                             */
/************************************************************************/

OGRFeature *OGRNTFRasterLayer::GetFeature( long nFeatureId )

{
    int         iReqColumn, iReqRow;
    
/* -------------------------------------------------------------------- */
/*      Is this in the range of legal feature ids (pixels)?             */
/* -------------------------------------------------------------------- */
    if( nFeatureId < 1
        || nFeatureId > poReader->GetRasterXSize()*poReader->GetRasterYSize() )
    {
        return NULL;
    }

/* -------------------------------------------------------------------- */
/*      Do we need to load a different column.                          */
/* -------------------------------------------------------------------- */
    iReqColumn = (nFeatureId - 1) / poReader->GetRasterYSize();
    iReqRow = nFeatureId - iReqColumn * poReader->GetRasterXSize() - 1;
    
    if( iReqColumn != iColumnOffset )
    {
        iColumnOffset = iReqColumn;
        if( poReader->ReadRasterColumn( iReqColumn, pafColumn ) != CE_None )
            return NULL;
    }
    
/* -------------------------------------------------------------------- */
/*      Create a corresponding feature.                                 */
/* -------------------------------------------------------------------- */
    OGRFeature  *poFeature = new OGRFeature( poFeatureDefn );
    double      *padfGeoTransform = poReader->GetGeoTransform();

    poFeature->SetFID( nFeatureId );

    // NOTE: unusual use of GeoTransform - the pixel origin is the
    // bottom left corner!
    poFeature->SetGeometryDirectly(
        new OGRPoint( padfGeoTransform[0] + padfGeoTransform[1] * iReqColumn,
                      padfGeoTransform[3] + padfGeoTransform[5] * iReqRow,
                      pafColumn[iReqRow] ) );
    poFeature->SetField( 0, (int) pafColumn[iReqRow] );
    
    return poFeature;
}

/************************************************************************/
/*                          GetFeatureCount()                           */
/*                                                                      */
/*      If a spatial filter is in effect, we turn control over to       */
/*      the generic counter.  Otherwise we return the total count.      */
/*      Eventually we should consider implementing a more efficient     */
/*      way of counting features matching a spatial query.              */
/************************************************************************/

int OGRNTFRasterLayer::GetFeatureCount( int bForce )

{
    return nFeatureCount;
}

/************************************************************************/
/*                           GetSpatialRef()                            */
/************************************************************************/

OGRSpatialReference *OGRNTFRasterLayer::GetSpatialRef()

{
    return poDS->GetSpatialRef();
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRNTFRasterLayer::TestCapability( const char * pszCap )

{
    if( EQUAL(pszCap,OLCRandomRead) )
        return TRUE;

    else if( EQUAL(pszCap,OLCSequentialWrite) 
             || EQUAL(pszCap,OLCRandomWrite) )
        return FALSE;

    else if( EQUAL(pszCap,OLCFastFeatureCount) )
        return TRUE;

    else if( EQUAL(pszCap,OLCFastSpatialFilter) )
        return FALSE;

    else 
        return FALSE;
}