minor changes to improve structure

Author: dacoex

pvlib/io/iotools.py

@@ -0,0 +1,31 @@
+import pytz
+# How to get a time zone from a location using 
+# latitude and longitude coordinates?
+# http://stackoverflow.com/a/16086964
+# upstream: https://github.com/MrMinimal64/timezonefinder
+from timezonefinder import TimezoneFinder
+
+def get_loc_latlon(lat, lon):
+    """Returns the timezone for a coordinate pair.
+    """
+    
+    
+    tf = TimezoneFinder()
+    tz = tf.timezone_at(lng=lon, lat=lat)
+    
+    return tz
+    
+def localise_df(df_notz, tz_source_str='UTC', tz_target_str):
+    """
+    localises a pandas.DataFrame (df) to the target time zone of the pvlib-Location    
+    
+    Assumes that the input df does not have a timezone
+    
+    """
+    
+    tz_source_str = pytz.timezone(tz_source_str)
+    tz_target = pytz.timezone(tz_target_str)
+    
+    df_tz_target = df_notz.tz_convert(tz_source)
+    
+    return df_tz_target

pvlib/io/maccrad.py

@@ -1,12 +1,23 @@
+# standard library imports 
+import logging
+
+# related third party imports
 import pandas as pd
+import pytz
+
+# local application/library specific imports 
+from pvlib.location import Location
+from pvlib.io.iotools import get_loc_latlon, localise_df
 
 # required dateconverters
 def dtp_soda_pro_macc_rad(date):
-    "datetime converter for MACC-RAD data and others
+    """
+    datetime converter for MACC-RAD data and others
+    """
     datetime_stamp = date.split('/')[0]
 
     return datetime_stamp
-   
+    
 #XXX read metadata / header
 
 def read_maccrad_metadata(file_csv, name='maccrad'):
@@ -39,36 +50,90 @@ def read_maccrad_metadata(file_csv, name='maccrad'):
             alt_line = line
             alt = float(alt_line.split(':')[1])
     #        alt = float(line.split(':')[1])
+        if "Time reference" in line:
+            if "Universal time (UT)" in line:
+                tz_raw = 'UTC'
+            else:
+                logging.debug('No metadata on timezone found in input file')
+                logging.debug('Assuming UTC as default timezone')
+                tz_raw = 'UTC'
+
+    tz_loc = get_loc_latlon(lat, lon)
 
-    # How to get a time zone from a location using 
-    # latitude and longitude coordinates?
-    # http://stackoverflow.com/a/16086964
-    # upstream: https://github.com/MrMinimal64/timezonefinder
-    from timezonefinder import TimezoneFinder
-    tf = TimezoneFinder()
-    tz = tf.timezone_at(lng=lon, lat=lat)
 
-    from pvlib.location import Location
 
     location = Location(lat, lon, name=name, altitude=alt,
-                           tz=tz)
+                           tz=tz_loc)
+    
+    return tz_raw, location
+    
+def maccrad_df_to_pvlib(df_raw, tz_raw, loc, localise=True):
+    """Change some properties of the dataframe to be more compliant with pvlib
     
-    return location
+    * localisation
+    * column renaming
+    
+    """
+
+    if localise:
+        # timezone localisations
+        df_pvlib = localise_df(df_raw, tz_source_str=tz_raw, loc.tz)
+    # column renaming
+    df_pvlib.index.name = 'datetime'
+  
+    return df_pvlib
+    
+#def maccrad_df_to_pvlib(df):
+#    
+#    
+#    pass
+   
 
 #XXX read data
-def read_maccrad(file_csv, output='df'):
+def read_maccrad(file_csv, loc_name=None, skiprows=40, output='all'):
     """
     Read MACC-RAD current format for files into a pvlib-ready dataframe
+    
+    Parameters
+    ----------
+    file_csv : a csv file corresponding to the reader format   
+    skiprows : skiprows as in pandas.io.read_csv
+        The example files require skipping 40 rows.
+    output : all / loc / df_pvlib        
+        df_raw returns only the a pandas.DataFrame using the raw data from the 
+                        file (this can be helpful for debugging and comparison 
+                        with restuls obtained with other programs, e.g. 
+                        spreadsheet)
+        all returns df_raw, returns a pandas.DataFrame reformatted to match the 
+                         `variable naming convention <variables_style_rules>`
+                         for pvliball outputs, and a location created from 
+                         the metadata in raw input file header
+                         as tuple
+
+    
     """
-    df = pd.read_csv(file_csv, sep=';', skiprows=40, header=0,
+    df_raw = pd.read_csv(file_csv, sep=';', skiprows=skiprows, header=0,
                       index_col=0, parse_dates=True,
                       date_parser=dtp_soda_pro_macc_rad)
-    
-    if output == 'loc':
-        loc = read_maccrad_metadata(file_csv)
-        res = (loc, df)
+#TODO: add loc_name
+#TODO: add reformat needs loc!
+#TODO: add simplify output options raw or all
+    if output == 'df_raw':
+        res = df_raw
+    if output == 'test':
+        res = df_pvlib
     else:
-        res = df
+        tz_raw, loc = read_maccrad_metadata(file_csv)
+        df_pvlib = maccrad_df_to_pvlib(df_raw, tz_raw, loc, localise=True)
+        res = (df_raw, df_pvlib, loc)
+#    if output == 'loc':
+#        
+#        res = loc, df
+#    if output == 'all':
+#        # not calculated outside conditional to reduce overhead of metadata 
+#        # reading if not desired
+#        loc = read_maccrad_metadata(file_csv)
+#        res = (df_raw, df_pvlib, loc)
 
 
     return res

pvlib/test/test_io_maccrad.py

@@ -1,5 +1,7 @@
+# standard library imports 
 import os
 
+# local application/library specific imports 
 from pvlib.io.maccrad import read_maccrad
 
 
@@ -10,14 +12,16 @@
 maccrad_csv_dir = os.path.join("..", "..", "..", "pvlib_data", "MACC-RAD", "carpentras")
 maccrad_csv_path = os.path.join(maccrad_csv_dir, maccrad_csv)
 
-data_maccrad = read_maccrad(maccrad_csv_path, output='loc')
+data_maccrad = read_maccrad(maccrad_csv_path, output='all')
+data_maccrad = read_maccrad(maccrad_csv_path, output='test')
 
 maccrad_loc = data_maccrad[0]
 maccrad_df = data_maccrad[1]
 
 def test_location_coord():
-    assert (44.0830, 5.0590, 97.00) == (maccrad_loc.latitude, maccrad_loc.longitude, 
-                             maccrad_loc.altitude)
+    assert (44.0830, 5.0590, 97.00) == (maccrad_loc.latitude, 
+                                        maccrad_loc.longitude, 
+                                        maccrad_loc.altitude)
 
 
 def test_location_tz():