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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 @@ -81,6 +81,16 @@ 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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4 changes: 3 additions & 1 deletion docs/sphinx/source/whatsnew/v0.13.1.rst
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,9 @@ 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`)

Documentation
~~~~~~~~~~~~~
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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 @@ -39,3 +39,5 @@
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
337 changes: 337 additions & 0 deletions pvlib/iotools/meteonorm.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,337 @@
"""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 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, optional
First timestamp of the requested period. If a timezone is not
specified, UTC is assumed. A relative datetime string is also allowed.
end: datetime like, optional
Last timestamp of the requested period. If a timezone is not
specified, UTC is assumed. A relative datetime string is also allowed.
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'`` - forcast with hourly resolution
* ``'/forecast/precision'`` - forecast with 15-min resolution

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

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,
}

# convert list to string with values separated by commas
if not isinstance(params['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 horizon not in ['auto', 'flat']:
params['horizon'] = ','.join(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), headers=headers, params=params)
print(response)
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, optional
List of parameters to request or 'all' to get all parameters. The
default is 'all'.
surface_tilt: float, optional
Tilt angle from horizontal plane. The default is 0.
surface_azimuth : float, optional
Orientation (azimuth angle) of the (fixed) plane. Clockwise from north
(north=0, east=90, south=180, west=270). The default is 180.
time_step: {'1min', '1h'}, optional
Frequency of the time series. The default is '1h'.
horizon: optional
Specification of the hoirzon line. Can be either 'flat' or 'auto', or
specified as a list of 360 horizon elevation angles. The default is
'auto'.
terrain: string, optional
Local terrain situation. Must be one of: ['open', 'depression',
'cold_air_lake', 'sea_lake', 'city', 'slope_south',
'slope_west_east']. The default is 'open'.
albedo: float, optional
Ground albedo. Albedo changes due to snow fall are modelled. The
default is 0.2.
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 : {'esra', 'solis'}
Which clearsky model to use. The default is 'esra'.
data_version : string, optional
Version of Meteonorm climatological data to be used. The default is
'latest'.
future_scenario: string, optional
Future climate scenario.
future_year : integer, optional
Central year for a 20-year reference period in the future.
interval_index: bool, optional
Whether the index of the returned data object is of the type
pd.DatetimeIndex or pd.IntervalIndex. This is an experimental feature
which may be removed without warning. The default is False.
map_variables: bool, optional
When true, renames columns of the Dataframe to pvlib variable names
where applicable. See variable :const:`VARIABLE_MAP`. The default is
True.
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,
'terrain': terrain,
'turbidity': turbidity,
'clear_sky_radiation_model': clear_sky_radiation_model,
'data_version': data_version,
}

# convert list to string with values separated by commas
if not isinstance(params['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 horizon not in ['auto', 'flat']:
params['horizon'] = ','.join(horizon)

if turbidity != 'auto':
params['turbidity'] = ','.join(turbidity)

if random_seed is not None:
params['random_seed'] = random_seed

if future_scenario is not None:
params['future_scenario'] = future_scenario

if future_year is not None:
params['future_year'] = future_year

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

response = requests.get(
urljoin(url, TMY_ENDPOINT), 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='both',
)
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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