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10 changes: 10 additions & 0 deletions docs/sphinx/source/reference/iotools.rst
Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,16 @@ Commercial datasets
Accessing these APIs typically requires payment.
Datasets provide near-global coverage.

Meteonorm
*********

.. autosummary::
:toctree: generated/

iotools.get_meteonorm

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For Solcast there are specialized functions for retrieving TMY, historical and forecast data. For Meteonorm there is currently only a TMY and a "everthing else" getter function (for the endpoints /observation/training, /observation/realtime, /forecast/basic, and /forecast/precision). What's the reasoning behind implementing get_meteonorm instead of get_meteonorm_observation_training, get_meteonorm_observation_realtime, get_meteonorm_forecast_basic, and get_meteonorm_forecast_precision? There are pros and cons for both variants, but i would argue, that for the end user it's easier if there's a specialized function for every endpoint.

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@AdamRJensen AdamRJensen Aug 4, 2025

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I might be convinced to have a separate function for get_meteonorm_observation and get_meteonorm_forecast with a keyword parameter to switch between the subcases. The main motivation is to reduce the duplicate docstring and reduce the maintenance burden.

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I'm not sure what the right answer here is. Maybe @AdamRJensen's proposal is the best balance.

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@maschwanden maschwanden Aug 5, 2025

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Yes, I see that this is a maintenance nightmare with doc-strings of this size.
I assume messing around with the __doc__ field to share a part of the documentation is not really an option; this becomes unreadable very fast.

Despite that, every request to the API costs the user real money and thus I'm critical about using parameters - instead of separate functions - to decide which endpoint to call.

[...] keyword parameter to switch between the subcases.

@AdamRJensen How would this look like? One option would be to use the exact same signature but the value to the parameter endpoint has to be "basic"/"precision" for get_meteonorm_forecast and "realtime"/"training" for get_meteonorm_observation.
Note that there is no parameter frequency for the /forecast/basic endpoint, thus it would be a good idea to raise a warning or exception if the user uses endpoint="basic", time_step="1min".

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@AdamRJensen How would this look like? One option would be to use the exact same signature but the value to the parameter endpoint has to be "basic"/"precision" for get_meteonorm_forecast and "realtime"/"training" for get_meteonorm_observation. Note that there is no parameter frequency for the /forecast/basic endpoint, thus it would be a good idea to raise a warning or exception if the user uses endpoint="basic", time_step="1min".

@maschwanden If we are to split it into separate forecast and observation functions, then this is exactly how I envisioned it. I'm curious what other members of @pvlib/pvlib-maintainer have to say about this.

Also, I've added an error message if the basic forecast is requested with a frequency other than '1_hour'.

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@maschwanden Check out the changes in the last commit. Would this approach be ok with you?

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If I understand correctly, @maschwanden proposed meteonorm.get_meteonorm_observation_training is similar to the existing solcast.get_solcast_historic function and the meteonorm.get_meteonorm_observation_realtime is similar to the solcast.get_solcast_live function. I would favor API parallelism over concerns about docstrings.

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@maschwanden maschwanden Aug 7, 2025

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Yes 👍, this looks good to me!

@wholmgren : Yes, that's what I proposed.

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I've revised it such that all end points now have their own functions.

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Looks good!

iotools.get_meteonorm_tmy


SolarAnywhere
*************

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3 changes: 3 additions & 0 deletions docs/sphinx/source/whatsnew/v0.13.1.rst
Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,9 @@ Bug fixes

Enhancements
~~~~~~~~~~~~
* Add iotools functions to retrieve irradiance and weather data from Meteonorm:
:py:func:`~pvlib.iotools.get_meteonorm` and :py:func:`~pvlib.iotools.get_meteonorm_tmy`.
(:pull:`2499`)
* Add :py:func:`pvlib.iotools.get_nasa_power` to retrieve data from NASA POWER free API.
(:pull:`2500`)
* :py:func:`pvlib.spectrum.spectral_factor_firstsolar` no longer emits warnings
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2 changes: 2 additions & 0 deletions pvlib/iotools/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -39,4 +39,6 @@
from pvlib.iotools.solcast import get_solcast_historic # noqa: F401
from pvlib.iotools.solcast import get_solcast_tmy # noqa: F401
from pvlib.iotools.solargis import get_solargis # noqa: F401
from pvlib.iotools.meteonorm import get_meteonorm # noqa: F401
from pvlib.iotools.meteonorm import get_meteonorm_tmy # noqa: F401
from pvlib.iotools.nasa_power import get_nasa_power # noqa: F401
349 changes: 349 additions & 0 deletions pvlib/iotools/meteonorm.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,349 @@
"""Functions for retrieving data from Meteonorm."""

import pandas as pd
import requests
from urllib.parse import urljoin

URL = 'https://api.meteonorm.com/v1/'

VARIABLE_MAP = {
'global_horizontal_irradiance': 'ghi',
'diffuse_horizontal_irradiance': 'dhi',
'direct_normal_irradiance': 'dni',
'direct_horizontal_irradiance': 'bhi',
'global_clear_sky_irradiance': 'ghi_clear',
'diffuse_tilted_irradiance': 'poa_diffuse',
'direct_tilted_irradiance': 'poa_direct',
'global_tilted_irradiance': 'poa',
'temperature': 'temp_air',
'dew_point_temperature': 'temp_dew',
}

TIME_STEP_MAP = {
'1h': '1_hour',
'h': '1_hour',
'15min': '15_minutes',
'1min': '1_minute',
'min': '1_minute',
}


def get_meteonorm(latitude, longitude, start, end, api_key, endpoint,
parameters='all', *, surface_tilt=0, surface_azimuth=180,
time_step='15min', horizon='auto', interval_index=False,
map_variables=True, url=URL):
"""
Retrieve irradiance and weather data from Meteonorm.

The Meteonorm data options are described in [1]_ and the API is described
in [2]_. A detailed list of API options can be found in [3]_.

This function supports retrieval of historical and forecast data, but not
TMY.

Parameters
----------
latitude : float
In decimal degrees, north is positive (ISO 19115).
longitude: float
In decimal degrees, east is positive (ISO 19115).
start : datetime like
First timestamp of the requested period. If a timezone is not
specified, UTC is assumed. Relative datetime strings are supported.
end : datetime like
Last timestamp of the requested period. If a timezone is not
specified, UTC is assumed. Relative datetime strings are supported.
api_key : str
Meteonorm API key.
endpoint : str
API endpoint, see [3]_. Must be one of:

* ``'observation/training'`` - historical data with a 7-day delay
* ``'observation/realtime'`` - near-real time (past 7-days)
* ``'forecast/basic'`` - forecast with hourly resolution
* ``'forecast/precision'`` - forecast with 15-min resolution

parameters : list or 'all', default : 'all'
List of parameters to request or `'all'` to get all parameters.
surface_tilt : float, default : 0
Tilt angle from horizontal plane.
surface_azimuth : float, default : 180
Orientation (azimuth angle) of the (fixed) plane. Clockwise from north
(north=0, east=90, south=180, west=270).
time_step : {'1min', '15min', '1h'}, default : '15min'
Frequency of the time series. The parameter is ignored when requesting
forcasting data.
horizon : str or list, default : 'auto'
Specification of the horizon line. Can be either a 'flat', 'auto', or
a list of 360 integer horizon elevation angles.
interval_index : bool, default : False
Index is pd.DatetimeIndex when False, and pd.IntervalIndex when True.
This is an experimental feature which may be removed without warning.
map_variables : bool, default : True
When true, renames columns of the Dataframe to pvlib variable names
where applicable. See variable :const:`VARIABLE_MAP`.
url : str, optional
Base URL of the Meteonorm API. The ``endpoint`` parameter is
appended to the url. The default is
:const:`pvlib.iotools.meteonorm.URL`.

Raises
------
requests.HTTPError
Raises an error when an incorrect request is made.

Returns
-------
data : pd.DataFrame
Time series data. The index corresponds to the start (left) of the
interval unless ``interval_index`` is set to False.
meta : dict
Metadata.

Examples
--------
>>> # Retrieve historical time series data
>>> df, meta = get_meteonorm( # doctest: +SKIP
... latitude=50, longitude=10, # doctest: +SKIP
... start='2023-01-01', end='2025-01-01', # doctest: +SKIP
... api_key='redacted', # doctest: +SKIP
... endpoint='observation/training') # doctest: +SKIP

See Also
--------
pvlib.iotools.get_meteonorm_tmy

References
----------
.. [1] `Meteonorm
<https://meteonorm.com/>`_
.. [2] `Meteonorm API
<https://docs.meteonorm.com/docs/getting-started>`_
.. [3] `Meteonorm API reference
<https://docs.meteonorm.com/api>`_
"""
start = pd.Timestamp(start)
end = pd.Timestamp(end)
start = start.tz_localize('UTC') if start.tzinfo is None else start
end = end.tz_localize('UTC') if end.tzinfo is None else end

params = {
'lat': latitude,
'lon': longitude,
'start': start.strftime('%Y-%m-%dT%H:%M:%SZ'),
'end': end.strftime('%Y-%m-%dT%H:%M:%SZ'),
'parameters': parameters,
'surface_tilt': surface_tilt,
'surface_azimuth': surface_azimuth,
'horizon': horizon,
}

# Allow specifying single parameters as string
if isinstance(parameters, str):
parameter_list = \
list(VARIABLE_MAP.keys()) + list(VARIABLE_MAP.values())
if parameters in parameter_list:
parameters = [parameters]

# convert list to string with values separated by commas
if not isinstance(parameters, (str, type(None))):
# allow the use of pvlib parameter names
parameter_dict = {v: k for k, v in VARIABLE_MAP.items()}
parameters = [parameter_dict.get(p, p) for p in parameters]
params['parameters'] = ','.join(parameters)

if not isinstance(horizon, str):
params['horizon'] = ','.join(map(str, horizon))

if 'forecast' not in endpoint.lower():
params['frequency'] = TIME_STEP_MAP.get(time_step, time_step)

headers = {"Authorization": f"Bearer {api_key}"}

response = requests.get(
urljoin(url, endpoint.lstrip('/')), headers=headers, params=params)

if not response.ok:
# response.raise_for_status() does not give a useful error message
raise requests.HTTPError(response.json())

data, meta = _parse_meteonorm(response, interval_index, map_variables)

return data, meta


TMY_ENDPOINT = 'climate/tmy'


def get_meteonorm_tmy(latitude, longitude, api_key,
parameters='all', *, surface_tilt=0,
surface_azimuth=180, time_step='15min', horizon='auto',
terrain='open', albedo=0.2, turbidity='auto',
random_seed=None, clear_sky_radiation_model='esra',
data_version='latest', future_scenario=None,
future_year=None, interval_index=False,
map_variables=True, url=URL):
"""
Retrieve TMY irradiance and weather data from Meteonorm.

The Meteonorm data options are described in [1]_ and the API is described
in [2]_. A detailed list of API options can be found in [3]_.

Parameters
----------
latitude : float
In decimal degrees, north is positive (ISO 19115).
longitude : float
In decimal degrees, east is positive (ISO 19115).
api_key : str
Meteonorm API key.
parameters : list or 'all', default : 'all'
List of parameters to request or `'all'` to get all parameters.
surface_tilt : float, default : 0
Tilt angle from horizontal plane.
surface_azimuth : float, default : 180
Orientation (azimuth angle) of the (fixed) plane. Clockwise from north
(north=0, east=90, south=180, west=270).
time_step : {'1min', '1h'}, default : '1h'
Frequency of the time series.
horizon : str, optional
Specification of the horizon line. Can be either 'flat' or 'auto', or
specified as a list of 360 integer horizon elevation angles.
'auto'.
terrain : str, default : 'open'
Local terrain situation. Must be one of: ['open', 'depression',
'cold_air_lake', 'sea_lake', 'city', 'slope_south',
'slope_west_east'].
albedo : float, default : 0.2
Ground albedo. Albedo changes due to snow fall are modelled.
turbidity : list or 'auto', optional
List of 12 monthly mean atmospheric Linke turbidity values. The default
is 'auto'.
random_seed : int, optional
Random seed to be used for stochastic processes. Two identical requests
with the same random seed will yield identical results.
clear_sky_radiation_model : str, default : 'esra'
Which clearsky model to use. Must be either `'esra'` or `'solis'`.
data_version : str, default : 'latest'
Version of Meteonorm climatological data to be used.
future_scenario : str, optional
Future climate scenario.
future_year : int, optional
Central year for a 20-year reference period in the future.
interval_index : bool, default : False
Index is pd.DatetimeIndex when False, and pd.IntervalIndex when True.
This is an experimental feature which may be removed without warning.
map_variables : bool, default : True
When true, renames columns of the Dataframe to pvlib variable names
where applicable. See variable :const:`VARIABLE_MAP`.
url : str, optional.
Base URL of the Meteonorm API. `'climate/tmy'` is
appended to the URL. The default is:
:const:`pvlib.iotools.meteonorm.URL`.

Raises
------
requests.HTTPError
Raises an error when an incorrect request is made.

Returns
-------
data : pd.DataFrame
Time series data. The index corresponds to the start (left) of the
interval unless ``interval_index`` is set to False.
meta : dict
Metadata.

See Also
--------
pvlib.iotools.get_meteonorm

References
----------
.. [1] `Meteonorm
<https://meteonorm.com/>`_
.. [2] `Meteonorm API
<https://docs.meteonorm.com/docs/getting-started>`_
.. [3] `Meteonorm API reference
<https://docs.meteonorm.com/api>`_
"""
params = {
'lat': latitude,
'lon': longitude,
'surface_tilt': surface_tilt,
'surface_azimuth': surface_azimuth,
'frequency': time_step,
'parameters': parameters,
'horizon': horizon,
'situation': terrain,
'turbidity': turbidity,
'clear_sky_radiation_model': clear_sky_radiation_model,
'data_version': data_version,
'random_seed': random_seed,
'future_scenario': future_scenario,
'future_year': future_year,
}

# Allow specifying single parameters as string
if isinstance(parameters, str):
parameter_list = \
list(VARIABLE_MAP.keys()) + list(VARIABLE_MAP.values())
if parameters in parameter_list:
parameters = [parameters]

# convert list to string with values separated by commas
if not isinstance(parameters, (str, type(None))):
# allow the use of pvlib parameter names
parameter_dict = {v: k for k, v in VARIABLE_MAP.items()}
parameters = [parameter_dict.get(p, p) for p in parameters]
params['parameters'] = ','.join(parameters)

if not isinstance(horizon, str):
params['horizon'] = ','.join(map(str, horizon))

if not isinstance(turbidity, str):
params['turbidity'] = ','.join(map(str, turbidity))

params['frequency'] = TIME_STEP_MAP.get(time_step, time_step)

headers = {"Authorization": f"Bearer {api_key}"}

response = requests.get(
urljoin(url, TMY_ENDPOINT.lstrip('/')), headers=headers, params=params)

if not response.ok:
# response.raise_for_status() does not give a useful error message
raise requests.HTTPError(response.json())

data, meta = _parse_meteonorm(response, interval_index, map_variables)

return data, meta


def _parse_meteonorm(response, interval_index, map_variables):
data_json = response.json()['values']
# identify empty columns
empty_columns = [k for k, v in data_json.items() if v is None]
# remove empty columns
_ = [data_json.pop(k) for k in empty_columns]

data = pd.DataFrame(data_json)

# xxx: experimental feature - see parameter description
if interval_index:
data.index = pd.IntervalIndex.from_arrays(
left=pd.to_datetime(response.json()['start_times']),
right=pd.to_datetime(response.json()['end_times']),
closed='left',
)
else:
data.index = pd.to_datetime(response.json()['start_times'])

meta = response.json()['meta']

if map_variables:
data = data.rename(columns=VARIABLE_MAP)
meta['latitude'] = meta.pop('lat')
meta['longitude'] = meta.pop('lon')

return data, meta
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