Remove airmass PWV scaling (#39)

Removes the airmass PWV scaling functionality

pwv_kpno/__init__.py

@@ -19,8 +19,8 @@
 """pwv_kpno provides models for the atmospheric transmission function due to
 precipitable water vapor (PWV). Using PWV measurements published
 by the SuomiNet project (https://www.suominet.ucar.edu), this package is
-capable of returning the modeled PWV transmission for a given date, time, and
-airmass at customizable geographic locations. By default, this functionality
+capable of returning the modeled PWV transmission for a given date and time
+at customizable geographic locations. By default, this functionality
 is set to model Kitt Peak National Observatory. Default models cover
 wavelengths from 3,000 to 12,000 Angstroms at a resolution of 0.05 Angstroms.
 
@@ -64,7 +64,7 @@
 ]
 
 __license__ = 'GPL V3'
-__version__ = '1.2.1'
+__version__ = '1.2.2'
 __email__ = 'djperrefort@pitt.edu'
 __status__ = 'Release'
 

pwv_kpno/pwv_atm.py

@@ -64,12 +64,6 @@
       >>> pwv_atm.trans_for_pwv(pwv, pwv_err)
 
 
-    To retrieve the atmospheric model for at the current site being modeled
-    at a given datetime and airmass:
-
-      >>> pwv_atm.trans_for_date(date=obsv_date,airmass=1.2,format=)
-
-
     To access the PWV measurements for the current site being modeled as an
     astropy table:
 
@@ -154,19 +148,16 @@ def _warn_available_data(
 
 def _pwv_date(
         date: Union[float, np.array, datetime],
-        airmass: float = 1,
         format: str = None,
         test_model: Table = None) \
         -> Tuple[Union[float, np.array], Union[float, np.array]]:
     """Returns the modeled PWV column density at the current site
 
     Interpolate from the modeled PWV column density at at the current site
-    being modeled and return the PWV column density for a given datetime and
-    airmass.
+    being modeled and return the PWV column density for a given datetime.
 
     Args:
         date: The date of the desired PWV column density
-        airmass: The airmass along line of sight
         format: An astropy compatible time format
         test_model: A mock PWV model used by the test suite
 
@@ -187,34 +178,27 @@ def _pwv_date(
     pwv = np.interp(time_stamp, pwv_model['date'], pwv_model['pwv'])
     pwv_err = np.interp(time_stamp, pwv_model['date'], pwv_model['pwv_err'])
 
-    # Determine the PWV level along line of sight as outlined in
-    # Horne et al. 2012
-    pwv_los = pwv * (airmass ** .6)
-    pwv_err_los = pwv_err * (airmass ** .6)
-    return pwv_los, pwv_err_los
+    return pwv, pwv_err
 
 
 def pwv_date(
-        date: Union[float, np.array, datetime],
-        airmass: float = 1,
-        format: str = None) \
+        date: Union[float, np.array, datetime], format: str = None) \
         -> Tuple[Union[float, np.array], Union[float, np.array]]:
     """Returns the modeled PWV column density at the current site
 
     Interpolate from the modeled PWV column density at the current site being
-    modeled and return the PWV column density for a given datetime and airmass.
+    modeled and return the PWV column density for a given datetime.
 
     Args:
         date: The date of the desired PWV column density
-        airmass: The airmass along line of sight
         format: An astropy compatible time format (e.g., unix, mjd, datetime)
 
     Returns:
         The modeled PWV column density at the current site
         The error in modeled PWV column density
     """
 
-    return _pwv_date(date, airmass, format)
+    return _pwv_date(date, format)
 
 
 def downloaded_years() -> List[int]:
@@ -464,12 +448,11 @@ def trans_for_pwv(
     return transmission
 
 
-def _raise_transmission_args(date: datetime, airmass: float):
+def _raise_transmission_args(date: datetime):
     """Raise exception if arguments have wrong type or value
 
     Args:
         date: A datetime value
-        airmass: An airmass value
     """
 
     if not isinstance(date, datetime):
@@ -487,21 +470,16 @@ def _raise_transmission_args(date: datetime, airmass: float):
         err_msg = "Cannot model dates in the future (passed {})"
         raise ValueError(err_msg.format(date))
 
-    if not isinstance(airmass, (float, int)):
-        raise TypeError("Argument 'airmass' (pos 2) must be an int or float")
-
 
 def _trans_for_date(
         date: Union[float, np.array, datetime],
-        airmass: float = 1,
         format: str = None,
         bins: Union[int, list] = None,
         test_model: Table = None) -> Table:
     """Return a model for the atmospheric transmission function due to PWV
 
     Args:
         date: The datetime of the desired model
-        airmass: The airmass of the desired model
         format: An astropy compatible time format
         bins: Integer number of bins or sequence of bin edges
         test_model: A mock PWV model used by the test suite
@@ -510,35 +488,32 @@ def _trans_for_date(
         The modeled transmission function as an astropy table
     """
 
-    pwv, pwv_err = _pwv_date(date, airmass=airmass, format=format,
-                             test_model=test_model)
+    pwv, pwv_err = _pwv_date(date, format=format, test_model=test_model)
 
     return trans_for_pwv(pwv, pwv_err, bins)
 
 
 def trans_for_date(
         date: Union[float, np.array, datetime],
-        airmass: float = 1,
         format: str = None,
         bins: Union[int, list] = None) -> Table:
     """Return a model for the atmospheric transmission function due to PWV
 
-    For a given datetime and airmass, return a model for the atmospheric
+    For a given datetime, return a model for the atmospheric
     transmission function due to precipitable water vapor at the current site
     being modeled. The transmission function can optionally be binned by
     specifying the `bins` argument.
 
     Args:
         date: The date of the desired model in the given format
-        airmass: The airmass of the desired model
         format: An astropy compatible time format (e.g., unix, mjd, datetime)
         bins: Integer number of bins or sequence of bin edges
 
     Returns:
         The modeled transmission function as an astropy table
     """
 
-    return _trans_for_date(date, airmass, format, bins)
+    return _trans_for_date(date, format, bins)
 
 
 def get_all_receiver_data(receiver_id: str, apply_cuts: bool = True):

tests/test_pwv_atm.py

@@ -185,40 +185,10 @@ def test_data_gap_handling(self):
                           1,
                           mock_model)
 
-    def test_airmass_dependence(self):
-        """PWV should be proportional to airmass ^ .6
-
-        This PWV airmass relation is presented in  Horne et al. 2012
-        """
-
-        test_date = datetime.utcfromtimestamp(self.pwv_model['date'][0])
-        test_date = test_date.replace(tzinfo=utc)
-        pwv, pwv_err = pwv_atm._pwv_date(test_date)
-        pwv_los, pwv_err_los = pwv_atm._pwv_date(test_date, airmass=2)
-
-        self.assertEqual(pwv_los, (2 ** .6) * pwv)
-        self.assertEqual(pwv_err_los, (2 ** .6) * pwv_err)
-
 
 class TransmissionErrors(TestCase):
     """Test pwv_kpno.transmission for raised errors due to bad arguments"""
 
-    def test_argument_types(self):
-        """Test errors raised from function call with wrong argument types"""
-
-        test_date = datetime(2011, 1, 5, 12, 47, tzinfo=utc)
-
-        # TypeError for date argument (should be datetime)
-        self.assertRaises(TypeError, pwv_atm._raise_transmission_args, "1", 1)
-
-        # TypeError for airmass argument (should be float or int)
-        self.assertRaises(TypeError, pwv_atm._raise_transmission_args,
-                          test_date, "1")
-
-        # ValueError due to naive datetime with no time zone info
-        self.assertRaises(ValueError, pwv_atm._raise_transmission_args,
-                          datetime.now(), 1)
-
     def test_argument_values(self):
         """Test errors raise from function call with date out of data range
 
@@ -228,17 +198,14 @@ def test_argument_values(self):
         """
 
         early_day = datetime(year=2009, month=12, day=31, tzinfo=utc)
-        self.assertRaises(ValueError, pwv_atm._raise_transmission_args,
-                          early_day, 1)
+        self.assertRaises(ValueError, pwv_atm._raise_transmission_args, early_day)
 
         now = datetime.now()
         late_day = now + timedelta(days=1)
-        self.assertRaises(ValueError, pwv_atm._raise_transmission_args,
-                          late_day, 1)
+        self.assertRaises(ValueError, pwv_atm._raise_transmission_args, late_day)
 
         late_year = datetime(year=now.year + 1, month=1, day=1, tzinfo=utc)
-        self.assertRaises(ValueError, pwv_atm._raise_transmission_args,
-                          late_year, 1)
+        self.assertRaises(ValueError, pwv_atm._raise_transmission_args, late_year)
 
 
 class TransmissionResults(TestCase):
@@ -269,7 +236,7 @@ def test_column_units(self):
         """
 
         sample_transm = pwv_atm.trans_for_date(
-            datetime(2011, 1, 1, tzinfo=utc), 1, format='datetime')
+            datetime(2011, 1, 1, tzinfo=utc), format='datetime')
         w_units = sample_transm['wavelength'].unit
         t_units = sample_transm['transmission'].unit