def _flds_shape(fieldname, header):
    """Compute shape of flds variable."""
    shp = list(header['nts'])
    shp.append(header['ntb'])
    # probably a better way to handle this
    if fieldname == 'Velocity':
        shp.insert(0, 3)
        # extra points
        header['xp'] = int(header['nts'][0] != 1)
        shp[1] += header['xp']
        header['yp'] = int(header['nts'][1] != 1)
        shp[2] += header['yp']
        header['zp'] = 1
        header['xyp'] = 1
    else:
        shp.insert(0, 1)
        header['xp'] = 0
        header['yp'] = 0
        header['zp'] = 0
        header['xyp'] = 0
    return shp
Compute shape of flds variable.