Re: [pysolar-discuss] Strange azimuth values

[Jay Doscher <jay@xxxxxxxxxxxxx>]

I found the same issue, and managed to successfully offset it in my python
code.  A disclaimer though- this works for me in the southwest US, and may
be different elsewhere.

def getsolarheading():
        Azimuth = Pysolar.GetAzimuth(maplat, maplon,
datetime.datetime.utcnow())
        if Azimuth < 0:
                if (Azimuth >= -180):
                        solarheading = ((Azimuth * -1) + 180)
                if (Azimuth < -180):
                        solarheading = ((Azimuth * -1) - 180)
        if Azimuth >= 0:
                solarheading = Azimuth
        return solarheading

This code will translate the Azimuth from Pysolar into a compass heading.
I'm not sure what to tell you about altitude.

Cheers,
Jay

On Sun, May 10, 2015 at 2:05 PM, Frank Lazzarini <flazzarini@xxxxxxxxx>
wrote:

> Hi there,
>
> when I run the following simulation I get really odd azimuth values. Well
> at least they seem odd, if I understood the documentation correctly they
> from ~90 over 0 to -90 degrees. When I run a simulation of an entire day I
> get really odd values for azimuth.
>
> from pysolar.solar import get_azimuth, get_altitude
> from datetime import datetime
> from pytz import timezone
>
>
> latitude = 49.707524
> longitude = 6.244362
> year = 2015
> month = 5
> day = 10
>
>
> def get_sun_position(latitude, longitude, time):
>     alt = get_altitude(latitude, longitude, time)
>     azi = get_azimuth(latitude, longitude, time)
>     return alt, azi
>
> tzinfo = timezone('Europe/Luxembourg')
> today = datetime.now(tz=tzinfo)
>
> for hour in range(0, 23):
>     time = datetime(
>         year,
>         month,
>         day,
>         hour,
>         0,
>         tzinfo=tzinfo
>     )
>     alt, azi = get_sun_position(latitude, longitude, time)
>     print("[{}] Altitude: {} Azimuth: {}".format(time, alt, azi))
>
>
> Now when I run this I get the following values
>
>
> [2015-05-10 00:00:00+00:25] Altitude: -22.817917957170042 Azimuth:
> -180.91958537964064
> [2015-05-10 01:00:00+00:25] Altitude: -21.35437669913535 Azimuth:
> -196.28249041016966
> [2015-05-10 02:00:00+00:25] Altitude: -17.460113361911073 Azimuth:
> -210.88264446553194
> [2015-05-10 03:00:00+00:25] Altitude: -11.530293822218377 Azimuth:
> -224.33485353947378
> [2015-05-10 04:00:00+00:25] Altitude: -4.041985922217601 Azimuth:
> -236.6422942983795
> [2015-05-10 05:00:00+00:25] Altitude: 4.721075310609919 Azimuth:
> -248.0844855824365
> [2015-05-10 06:00:00+00:25] Altitude: 13.916416678430616 Azimuth:
> -259.1019578849806
> [2015-05-10 07:00:00+00:25] Altitude: 23.540263468364685 Azimuth:
> -270.25884449955726
> [2015-05-10 08:00:00+00:25] Altitude: 33.162952138663265 Azimuth:
> -282.2912788132876
> [2015-05-10 09:00:00+00:25] Altitude: 42.311459924908625 Azimuth:
> -296.2279541178277
> [2015-05-10 10:00:00+00:25] Altitude: 50.279286820496274 Azimuth:
> -313.49311577994877
> [2015-05-10 11:00:00+00:25] Altitude: 55.94436234658116 Azimuth:
> -335.49523632286264
> [2015-05-10 12:00:00+00:25] Altitude: 57.89747249155467 Azimuth:
> -1.6026287381770885
> [2015-05-10 13:00:00+00:25] Altitude: 55.45948436540424 Azimuth:
> -27.402783821691315
> [2015-05-10 14:00:00+00:25] Altitude: 49.46294168127422 Azimuth:
> -48.82724611999379
> [2015-05-10 15:00:00+00:25] Altitude: 41.31880137304067 Azimuth:
> -65.63086306581897
> [2015-05-10 16:00:00+00:25] Altitude: 32.09659468953159 Azimuth:
> -79.28835550065156
> [2015-05-10 17:00:00+00:25] Altitude: 22.46665426651643 Azimuth:
> -91.18090530087704
> [2015-05-10 18:00:00+00:25] Altitude: 12.887187896956561 Azimuth:
> -102.29565250233105
> [2015-05-10 19:00:00+00:25] Altitude: 3.8032148272317357 Azimuth:
> -113.34291810798067
> [2015-05-10 20:00:00+00:25] Altitude: -4.854352153303335 Azimuth:
> -124.86962574438837
> [2015-05-10 21:00:00+00:25] Altitude: -12.152382809733522 Azimuth:
> -137.2976741424302
> [2015-05-10 22:00:00+00:25] Altitude: -17.83265833925366 Azimuth:
> -150.87639859009437
>
>
>
> Any ideas?
>
> --
>
> *Frank Lazzarini*
> *Email:* flazzarini@xxxxxxxxx  *Phone:* +352 621 314 430
> *Blog:*   http://www.gefoo.org   *LinkedIn:*
> http://www.linkedin.com/pub/frank-lazzarini/1a/a30/112
>
>