public   double [] readChunkDouble(DataChunk chunk, String name) {
		
		Variable v = nc.findVariable(name);
		if( v == null )
		{
			LOG.error("FILE varible "+name+" failure");
			return null;
		}
		try {
				return  (double [] )v.read(chunk.getStart(), chunk.getChunkSize()).copyTo1DJavaArray();
			} catch (IOException e) {
				
				e.printStackTrace();
			} catch (InvalidRangeException e) {
			
				e.printStackTrace();
			}
		return null;
	}