use timezone as arg, change output to timezone

Author: mikofski

pvlib/solarposition.py

@@ -206,7 +206,7 @@ def spa_c(time, latitude, longitude, pressure=101325, altitude=0,
     spa_df = pd.DataFrame(spa_out, index=time)
 
     if raw_spa_output:
-        return spa_df
+        return spa_df.rename(columns={'time_zone': 'timezone'})
     else:
         dfout = pd.DataFrame({'azimuth': spa_df['azimuth'],
                               'apparent_zenith': spa_df['zenith'],

pvlib/spa_c_files/spa_py.c

@@ -1,6 +1,6 @@
 cimport cspa_py
 
-def spa_calc(year, month, day, hour, minute, second, time_zone, latitude,
+def spa_calc(year, month, day, hour, minute, second, timezone, latitude,
         longitude, elevation, pressure, temperature, delta_t,
         delta_ut1=0, slope=30.0, azm_rotation=-10, atmos_refract=0.5667):
 
@@ -12,7 +12,7 @@ def spa_calc(year, month, day, hour, minute, second, time_zone, latitude,
     spa.hour = hour
     spa.minute = minute
     spa.second = second
-    spa.time_zone = time_zone
+    spa.time_zone = timezone
     spa.delta_ut1 = delta_ut1
     spa.delta_t = delta_t
     spa.longitude = longitude

pvlib/spa_c_files/spa_py.pyx

@@ -35,7 +35,7 @@
 def spa_calc_example(test=True):
     result = spa_calc(
         year=2004, month=10, day=17, hour=12, minute=30, second=30,
-        time_zone=-7, longitude=-105.1786, latitude=39.742476,
+        timezone=-7, longitude=-105.1786, latitude=39.742476,
         elevation=1830.14, pressure=820, temperature=11, delta_t=67
     )
     if test: