def test_1ms_vel_message():
# read in a velocity message from a MSG1 file
uncompressed_file = bz2.BZ2File(
pyart.testing.NEXRAD_ARCHIVE_MSG1_FILE, 'rb')
# seek pack the volume header, compression header and reflectivity data
uncompressed_file.seek(24 + 12 + 897408)
buf = uncompressed_file.read(2432) # read a record
# create a fake message with a 1 m/s velocity resolution
fake_buf = buf[:16+43] + b'\x04' + buf[16+44:]
# check the velocity scale
new_pos, dic = nexrad_level2._get_record_from_buf(fake_buf, 0)
assert dic['VEL']['scale'] == 1.0
def test_1ms_vel_message():
# read in a velocity message from a MSG1 file
uncompressed_file = bz2.BZ2File(pyart.testing.NEXRAD_ARCHIVE_MSG1_FILE,
'rb')
# seek pack the volume header, compression header and reflectivity data
uncompressed_file.seek(24 + 12 + 897408)
buf = uncompressed_file.read(2432) # read a record
# create a fake message with a 1 m/s velocity resolution
fake_buf = buf[:16 + 43] + b'\x04' + buf[16 + 44:]
# check the velocity scale
new_pos, dic = nexrad_level2._get_record_from_buf(fake_buf, 0)
assert dic['VEL']['scale'] == 1.0
# read in the first 134 records as write as is
out.write(fin.read(24 + 12 + RECORD_SIZE * 134))
# read the rest of the file, and create a array of int8
buf = fin.read()
buf_length = len(buf)
buf_data = np.frombuffer(buf, dtype='i1')
fin.close()
# replace all radial data with a single value so it compresses well
pos = 0
while pos < buf_length:
# retrieve the record (msg31)
new_pos, record = nexrad._get_record_from_buf(buf, pos)
if record['header']['type'] != 31:
pos += RECORD_SIZE
continue
# dummy out all moments
for bp_number in [4, 5, 6, 7, 8, 9]:
bp_str = 'block_pointer_' + str(bp_number)
block_pointer = record['msg_header'][bp_str]
if block_pointer != 0:
bpos = pos + block_pointer + MSG_HEADER_SIZE
d = nexrad._unpack_from_buf(buf, bpos, nexrad.GENERIC_DATA_BLOCK)
points = d['ngates']
if d['data_name'] == 'PHI':
points *= 2
start = pos + MSG_HEADER_SIZE + DATA_BLOCK_SIZE + block_pointer
# read in the first 134 records as write as is
out.write(fin.read(24 + 12 + RECORD_SIZE * 134))
# read the rest of the file, and create a array of int8
buf = fin.read()
buf_length = len(buf)
buf_data = np.frombuffer(buf, dtype='i1')
fin.close()
# replace all radial data with a single value so it compresses well
pos = 0
while pos < buf_length:
# retrieve the record (msg31)
new_pos, record = nexrad._get_record_from_buf(buf, pos)
if record['header']['type'] != 31:
pos += RECORD_SIZE
continue
# dummy out all moments
for bp_number in [4, 5, 6, 7, 8, 9]:
bp_str = 'block_pointer_' + str(bp_number)
block_pointer = record['msg_header'][bp_str]
if block_pointer != 0:
bpos = pos + block_pointer + MSG_HEADER_SIZE
d = nexrad._unpack_from_buf(buf, bpos, nexrad.GENERIC_DATA_BLOCK)
points = d['ngates']
if d['data_name'] == 'PHI':
points *= 2
start = pos + MSG_HEADER_SIZE + DATA_BLOCK_SIZE + block_pointer
