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Daniel Lassahn
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Rename function, use existend equation of time function, whatsnew in 7.0.0.
1 parent b20ca53 commit fe5bf63

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-147
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6 files changed

+127
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lines changed

‎docs/sphinx/source/api.rst

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -45,7 +45,7 @@ unless you know that you need a different function.
4545
solarposition.ephemeris
4646
solarposition.pyephem
4747
solarposition.spa_c
48-
solarposition.spencer_mc
48+
solarposition.spencer
4949

5050

5151
Additional functions for quantities closely related to solar position.

‎docs/sphinx/source/whatsnew/v0.7.0.rst

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -8,8 +8,11 @@ recommend all users of v0.6.3 upgrade to this release.
88

99
**Python 2.7 support ended on June 1, 2019**. (:issue:`501`)
1010

11+
- Add a faster way to calculate the solar position (`spencer`)
12+
1113

1214
Contributors
1315
~~~~~~~~~~~~
1416
* Mark Campanellli (:ghuser:`markcampanelli`)
1517
* Will Holmgren (:ghuser:`wholmgren`)
18+
* Daniel Lassahn (:ghuser:`meteoDaniel`)

‎docs/sphinx/source/whatsnew/v0.7.1.rst

Lines changed: 0 additions & 11 deletions
This file was deleted.

‎pvlib/solarposition.py

Lines changed: 14 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -68,7 +68,7 @@ def get_solarposition(time, latitude, longitude,
6868
6969
'nrel_c' uses the NREL SPA C code [3]: :py:func:`spa_c`
7070
71-
'spencer_mc' uses the Spencer formula [4] :py:func:`spencer_mc`
71+
'spencer' uses the Spencer formula [4] :py:func:`spencer`
7272
7373
7474
temperature : float, default 12
@@ -120,8 +120,8 @@ def get_solarposition(time, latitude, longitude,
120120
temperature=temperature, **kwargs)
121121
elif method == 'ephemeris':
122122
ephem_df = ephemeris(time, latitude, longitude, pressure, temperature)
123-
elif method == 'spencer_mc':
124-
ephem_df = spencer_mc(time, latitude, longitude)
123+
elif method == 'spencer':
124+
ephem_df = spencer(time, latitude, longitude)
125125

126126
else:
127127
raise ValueError('Invalid solar position method')
@@ -1456,14 +1456,13 @@ def sun_rise_set_transit_geometric(times, latitude, longitude, declination,
14561456
return sunrise, sunset, transit
14571457

14581458

1459-
def spencer_mc(times, latitude, longitude):
1459+
def spencer(times, latitude, longitude):
14601460
"""
1461-
Calculate the solar position using a python implementation of the
1462-
Spencer (1972) formulation provided by meteocontrol
1461+
Calculate the solar position using a formulation by Spencer 1971/1972.
14631462
14641463
Parameters
14651464
----------
1466-
times : :class:`pandas.DatetimeIndex`
1465+
times : pandas.DatetimeIndex`
14671466
Corresponding timestamps, must be localized to the timezone for the
14681467
``latitude`` and ``longitude``.
14691468
latitude : float
@@ -1479,7 +1478,6 @@ def spencer_mc(times, latitude, longitude):
14791478
elevation (degrees),
14801479
azimuth (degrees),
14811480
equation_of_time (seconds),
1482-
eccentricity,
14831481
declination (degrees).
14841482
14851483
References
@@ -1493,28 +1491,13 @@ def spencer_mc(times, latitude, longitude):
14931491
julians = datetime_to_julian(times)
14941492
julians_2000 = np.asarray(julians, dtype=np.float) - JULIAN_2000
14951493

1496-
lat = np.radians(latitude)
1497-
1498-
# Compute fractional year (gamma) in radians
1499-
gamma = 2 * np.pi * (julians_2000 % JULIAN_YEARS) / JULIAN_YEARS
1500-
cos_gamma = np.cos(gamma), np.cos(gamma * 2), np.cos(gamma * 3)
1501-
sin_gamma = np.sin(gamma), np.sin(gamma * 2), np.sin(gamma * 3)
1494+
latitude_radians = np.radians(latitude)
15021495
day_time = (julians_2000 % 1) * 24
15031496

1504-
# Eccentricity: correction factor of the earth's orbit.
1505-
eccentricity = 1.00011 + 0.034221 * cos_gamma[0]
1506-
eccentricity += 0.001280 * sin_gamma[0]
1507-
eccentricity += 0.000719 * cos_gamma[1]
1508-
eccentricity += 0.000077 * sin_gamma[1]
1509-
15101497
declination = np.array(declination_spencer71(times.dayofyear))
15111498

15121499
# Equation of time (difference between standard time and solar time).
1513-
eot = 0.000075 + 0.001868 * cos_gamma[0]
1514-
eot -= 0.032077 * sin_gamma[0]
1515-
eot -= 0.014615 * cos_gamma[1]
1516-
eot -= 0.040849 * sin_gamma[1]
1517-
eot *= 229.18
1500+
eot = np.array(equation_of_time_spencer71(times.dayofyear))
15181501

15191502
# True local time
15201503
tlt = (day_time + longitude / 15 + eot / 60) % 24 - 12
@@ -1523,16 +1506,18 @@ def spencer_mc(times, latitude, longitude):
15231506
ha = np.radians(tlt * 15)
15241507

15251508
# Calculate sun elevation.
1526-
sin_sun_elevation = np.sin(declination) * np.sin(lat)
1527-
sin_sun_elevation += np.cos(declination) * np.cos(lat) * np.cos(ha)
1509+
sin_sun_elevation = (
1510+
np.sin(declination) * np.sin(latitude_radians) +
1511+
np.cos(declination) * np.cos(latitude_radians) * np.cos(ha)
1512+
)
15281513

15291514
# Compute the sun's elevation and zenith angle.
15301515
elevation = np.arcsin(sin_sun_elevation)
15311516
zenith = np.pi / 2 - elevation
15321517

15331518
# Compute the sun's azimuth angle.
1534-
y = -(np.sin(lat) * np.sin(elevation) - np.sin(declination)) \
1535-
/ (np.cos(lat) * np.cos(elevation))
1519+
y = -(np.sin(latitude_radians) * np.sin(elevation) - np.sin(declination)) \
1520+
/ (np.cos(latitude_radians) * np.cos(elevation))
15361521
azimuth = np.arccos(y)
15371522

15381523
# Convert azimuth angle from 0-pi to 0-2pi.
@@ -1542,7 +1527,6 @@ def spencer_mc(times, latitude, longitude):
15421527
result = pd.DataFrame({'zenith': np.degrees(zenith),
15431528
'elevation': np.degrees(elevation),
15441529
'azimuth': np.degrees(azimuth),
1545-
'eccentricity': eccentricity,
15461530
'declination': declination,
15471531
'equation_of_time': eot},
15481532
index=times)

‎pvlib/test/test_solarposition.py

Lines changed: 104 additions & 104 deletions
Original file line numberDiff line numberDiff line change
@@ -754,120 +754,120 @@ def test_sun_rise_set_transit_geometric(expected_rise_set_spa, golden_mst):
754754
atol=np.abs(expected_transit_error).max())
755755

756756

757-
def test_spencer_mc():
757+
def test_spencer():
758758
""" test for the calculation based on spencer 1972 """
759-
latitude = 48.367073
760-
longitude = 10.868378
761-
to_test = solarposition.spencer_mc(times,
762-
latitude,
763-
longitude)
759+
latitude = 32.2
760+
longitude = -111
761+
to_test = solarposition.spencer(times,
762+
latitude,
763+
longitude)
764764
np.testing.assert_array_almost_equal(
765765
to_test.zenith.values,
766766
np.array(
767-
[107.5944161, 107.08772172, 106.43116829, 105.62900042,
768-
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769-
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770-
92.82654495, 90.90448339, 88.90662551, 86.83908587,
771-
84.70775942, 82.51832403, 80.27625186, 77.98682746,
772-
75.65517374, 73.28628434, 70.88506165, 68.45636234,
773-
66.0050506, 63.53605921, 61.05446218, 58.56556086,
774-
56.07498558, 53.58881946, 51.11374884, 48.65724635,
775-
46.22779685, 43.83517458, 41.49078009, 39.20804631,
776-
37.00291337, 34.89435623, 32.90492124, 31.06117096,
777-
29.39385375, 27.93751303, 26.72916357, 25.80569641,
778-
25.19996401, 24.93609994, 25.02533181, 25.46381181,
779-
26.23337616, 27.30490594, 28.64295418, 30.21015627,
780-
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781-
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782-
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783-
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784-
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785-
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786-
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787-
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788-
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789-
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790-
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791-
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792-
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793-
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794-
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795-
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796-
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797-
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798-
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799-
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800-
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801-
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802-
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803-
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804-
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805-
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806-
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807-
59.79682723, 62.2828738, 64.75901269, 67.22006367,
808-
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809-
79.12642433, 81.39351992, 83.61071161, 85.77262406,
810-
87.87368475, 89.90810859, 91.86989066, 93.75280924,
811-
95.55043872, 97.25617485, 98.86327462, 100.36491047,
812-
101.75424074, 103.024497, 104.16908649, 105.1817084,
813-
106.05648115, 106.78807492, 107.3718441, 107.80395262,
814-
108.08148404, 108.20252959, 108.1662479, 107.97289173,
815-
107.64770976]
767+
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768+
72.54998112, 75.56768635, 78.55430954, 81.50634428,
769+
84.41996557, 87.29098172, 90.11478465, 92.88629624,
770+
95.5999124, 98.24944658, 100.8280723, 103.32826814,
771+
105.74177, 108.05953355, 110.2717148, 112.36767828,
772+
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773+
120.68669583, 121.83036181, 122.77236599, 123.50252116,
774+
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775+
123.76832862, 123.14002805, 122.29571959, 121.24479895,
776+
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777+
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778+
104.46589822, 102.00508468, 99.46207977, 96.84474584,
779+
94.16022733, 91.4150024, 88.61493961, 85.76535568,
780+
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781+
70.92896677, 67.86980202, 64.78731633, 61.68424611,
782+
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783+
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784+
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785+
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786+
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787+
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788+
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789+
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790+
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791+
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792+
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793+
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794+
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795+
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796+
114.32284084, 116.15413465, 117.83342459, 119.34789444,
797+
120.68475046, 121.83160023, 122.77689598, 123.51041877,
798+
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799+
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800+
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801+
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802+
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803+
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804+
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805+
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806+
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807+
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808+
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809+
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810+
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811+
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812+
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813+
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814+
47.60138827, 50.76510173, 53.91983782, 57.06295199,
815+
60.15714089]
816816
)
817817
)
818818

819819
np.testing.assert_array_almost_equal(
820820
to_test.azimuth.values,
821821
np.array(
822-
[9.95354884, 13.51797616, 17.04447274, 20.52491225,
823-
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824-
37.04147561, 40.14748222, 43.18691015, 46.1616283,
825-
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826-
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827-
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828-
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829-
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830-
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831-
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832-
140.99278628, 147.49394635, 154.51314061, 162.00583842,
833-
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834-
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835-
227.81263221, 233.06524098, 237.89058053, 242.3392101,
836-
246.46057573, 250.30054442, 253.90036735, 257.29648187,
837-
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838-
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839-
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840-
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841-
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842-
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843-
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844-
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845-
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846-
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847-
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848-
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849-
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850-
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851-
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852-
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853-
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854-
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869-
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870-
9.85597076]
822+
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823+
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835+
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838+
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839+
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840+
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841+
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871871
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872872
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873873

‎pvlib/test/test_tools.py

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import datetime
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import numpy as np
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import pandas as pd
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import pytest
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import pvlib.tools
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from pvlib import tools
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from pvlib.test.test_solarposition import times
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times = pd.date_range(start=datetime.datetime(2014, 6, 24),
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end=datetime.datetime(2014, 6, 26), freq='15Min')
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@pytest.mark.parametrize('keys, input_dict, expected', [

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