Allow dates to be strings in iotools get functions (#1800)

* Update get functions

* Update pvgis.py

* Update whatsnew and add get_cams

* Update whatsnews

* Update v0.10.2.rst

Author: AdamRJensen

docs/sphinx/source/whatsnew/v0.10.2.rst

@@ -11,6 +11,10 @@ Deprecations
 
 Enhancements
 ~~~~~~~~~~~~
+* Added support for dates to be specified as strings in the iotools get functions:
+  :py:func:`pvlib.iotools.get_pvgis_hourly`, :py:func:`pvlib.iotools.get_cams`,
+  :py:func:`pvlib.iotools.get_bsrn`, and :py:func:`pvlib.iotools.read_midc_raw_data_from_nrel`.
+  (:pull:`1800`)
 
 
 Bug fixes
@@ -31,4 +35,4 @@ Requirements
 
 Contributors
 ~~~~~~~~~~~~
-
+* Adam R. Jensen (:ghuser:`AdamRJensen`)

pvlib/iotools/bsrn.py

@@ -154,6 +154,10 @@ def get_bsrn(station, start, end, username, password,
     # The FTP server uses lowercase station abbreviations
     station = station.lower()
 
+    # Use pd.to_datetime so that strings (e.g. '2021-01-01') are accepted
+    start = pd.to_datetime(start)
+    end = pd.to_datetime(end)
+
     # Generate list files to download based on start/end (SSSMMYY.dat.gz)
     filenames = pd.date_range(
         start, end.replace(day=1) + pd.DateOffset(months=1), freq='1M')\

pvlib/iotools/midc.py

@@ -215,9 +215,9 @@ def read_midc_raw_data_from_nrel(site, start, end, variable_map={},
     ----------
     site: string
         The MIDC station id.
-    start: datetime
+    start: datetime-like
         Start date for requested data.
-    end: datetime
+    end: datetime-like
         End date for requested data.
     variable_map: dict
         A dictionary mapping MIDC field names to pvlib names. Used to
@@ -247,8 +247,8 @@ def read_midc_raw_data_from_nrel(site, start, end, variable_map={},
     for more details and considerations.
     """
     args = {'site': site,
-            'begin': start.strftime('%Y%m%d'),
-            'end': end.strftime('%Y%m%d')}
+            'begin': pd.to_datetime(start).strftime('%Y%m%d'),
+            'end': pd.to_datetime(end).strftime('%Y%m%d')}
     url = 'https://midcdmz.nrel.gov/apps/data_api.pl'
     # NOTE: just use requests.get(url, params=args) to build querystring
     # number of header columns and data columns do not always match,

pvlib/iotools/pvgis.py

@@ -217,9 +217,9 @@ def get_pvgis_hourly(latitude, longitude, start=None, end=None,
     if raddatabase is not None:
         params['raddatabase'] = raddatabase
     if start is not None:
-        params['startyear'] = start if isinstance(start, int) else start.year
+        params['startyear'] = start if isinstance(start, int) else pd.to_datetime(start).year  # noqa: E501
     if end is not None:
-        params['endyear'] = end if isinstance(end, int) else end.year
+        params['endyear'] = end if isinstance(end, int) else pd.to_datetime(end).year  # noqa: E501
     if peakpower is not None:
         params['peakpower'] = peakpower
 

pvlib/iotools/sodapro.py

@@ -47,8 +47,9 @@ def get_cams(latitude, longitude, start, end, email, identifier='mcclear',
              altitude=None, time_step='1h', time_ref='UT', verbose=False,
              integrated=False, label=None, map_variables=True,
              server=URL, timeout=30):
-    """
-    Retrieve time-series of radiation and/or clear-sky global, beam, and
+    """Retrieve irradiance and clear-sky time series from CAMS.
+
+    Time-series of radiation and/or clear-sky global, beam, and
     diffuse radiation from CAMS (see [1]_). Data is retrieved from SoDa [2]_.
 
     Time coverage: 2004-01-01 to two days ago
@@ -65,9 +66,9 @@ def get_cams(latitude, longitude, start, end, email, identifier='mcclear',
         in decimal degrees, between -90 and 90, north is positive (ISO 19115)
     longitude : float
         in decimal degrees, between -180 and 180, east is positive (ISO 19115)
-    start: datetime like
+    start: datetime-like
         First day of the requested period
-    end: datetime like
+    end: datetime-like
         Last day of the requested period
     email: str
         Email address linked to a SoDa account
@@ -177,8 +178,8 @@ def get_cams(latitude, longitude, start, end, email, identifier='mcclear',
         altitude = -999
 
     # Start and end date should be in the format: yyyy-mm-dd
-    start = start.strftime('%Y-%m-%d')
-    end = end.strftime('%Y-%m-%d')
+    start = pd.to_datetime(start).strftime('%Y-%m-%d')
+    end = pd.to_datetime(end).strftime('%Y-%m-%d')
 
     email = email.replace('@', '%2540')  # Format email address
     identifier = 'get_{}'.format(identifier.lower())  # Format identifier str

pvlib/iotools/srml.py

@@ -243,9 +243,9 @@ def get_srml(station, start, end, filetype='PO', map_variables=True,
     ----------
     station : str
         Two letter station abbreviation.
-    start : datetime like
+    start : datetime-like
         First day of the requested period
-    end : datetime like
+    end : datetime-like
         Last day of the requested period
     filetype : string, default: 'PO'
         SRML file type to gather. See notes for explanation.