visad/src/main/java/ucar/nc2/iosp/gempak/GempakSurfaceIOSP.java
public boolean isValidFile(RandomAccessFile raf) throws IOException {
    if (!super.isValidFile(raf)) {
      return false;
    }
    // TODO:  handle other types of surface files
    return gemreader.getFileSubType()
            .equals(GempakSurfaceFileReader.STANDARD) || gemreader
            .getFileSubType().equals(GempakSurfaceFileReader.SHIP);
  }
public boolean isValidFile(RandomAccessFile raf) throws IOException {
    if (!super.isValidFile(raf)) {
      return false;
    }
    // TODO:  handle other types of surface files
    return gemreader.getFileSubType()
            .equals(GempakSurfaceFileReader.STANDARD) || gemreader
            .getFileSubType().equals(GempakSurfaceFileReader.SHIP);
  }
Is this a valid file?

@param raf RandomAccessFile to check
@return true if a valid Gempak grid file
@throws IOException problem reading file