# Copyright 2018 – present The UBC EOAS MOAD Group
# and The University of British Columbia
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# https://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# SPDX-License-Identifier: Apache-2.0
"""Functions for downloading observations data from web services.
"""
import logging
import urllib.error
import pandas
from moad_tools.places import PLACES
logging.getLogger(__name__).addHandler(logging.NullHandler())
[docs]
def get_ndbc_buoy(buoy_id):
"""Retrieve a collection of time series of the last 45 days of real-time observed
buoy data for an ECCC or NOAA data buoy from the NOAA National Data Buoy Center (NDBC)
https://www.ndbc.noaa.gov/data/realtime2/ web service.
The time series is returned as a :py:class:`pandas.DataFrame` object.
The returned time series date/time index is UTC.
:param int or str buoy_id: Buoy number or name.
Names use :py:obj:`moad_tools.places.PLACES` to
look up the buoy number.
:return: Buoy data time series.
:rtype: :py:class:`pandas.DataFrame`
"""
endpoint = "https://www.ndbc.noaa.gov/data/realtime2/"
msg = f"retrieving available real-time buoy data from {endpoint}"
try:
buoy_number = int(buoy_id)
except ValueError:
try:
buoy_number = f"{PLACES[buoy_id]['EC buoy number']}"
except KeyError as exc:
logging.error(
f"buoy id not found in places.PLACES: {buoy_id}; "
f"maybe try an integer buoy number?"
)
raise KeyError(
f"place name or info key not found in moad_tools.places.PLACES: {exc}"
)
msg = " ".join(
(
msg,
f"for buoy {buoy_number}"
if int(buoy_number) == buoy_id
else f"for buoy {buoy_number} {buoy_id}",
)
)
logging.info(msg)
ndbc_url = f"{endpoint}{buoy_number}.txt"
try:
try:
df = pandas.read_csv(
ndbc_url,
delim_whitespace=True,
header=[0, 1],
na_values="MM",
parse_dates=[[0, 1, 2, 3, 4]],
date_parser=lambda x: pandas.to_datetime(x, format="%Y %m %d %H %M"),
)
except urllib.error.URLError:
# Work around SSL: UNKNOWN_PROTOCOL error that appeared on 23may18
# by trying HTTP instead of HTTPS
ndbc_url = ndbc_url.replace("https://", "http://")
df = pandas.read_csv(
ndbc_url,
delim_whitespace=True,
header=[0, 1],
na_values="MM",
parse_dates=[[0, 1, 2, 3, 4]],
date_parser=lambda x: pandas.to_datetime(x, format="%Y %m %d %H %M"),
)
except urllib.error.HTTPError as exc:
msg = (
f"buoy data request failed: HTTP Error {exc.code}: {exc.reason}: {ndbc_url}"
)
logging.error(msg)
raise ValueError(msg) from exc
df.set_index(df.columns[0], inplace=True)
df.index.rename("time", inplace=True)
df.sort_index(inplace=True)
return df