update solar_position docstring

[mikofski]

• change units for pressure to mbars

[adriesse]

Does this have any repercussions for the solar position calculations? It seems that Pa are used everywhere else in PVLIB. Is this converted to mbar where necessary? pvlib.solarposition.get_solarposition appears to use Pa.

[mikofski]

No, the conversion is already handled in pvlib.solarposition.spa_python by dividing pressure by 100(mbar/PA) https://github.com/pvlib/pvlib-python/blob/master/pvlib/solarposition.py

[wholmgren]

Good catch, Mark. I suppose we could also change the API to make it more consistent, but I prefer the quick doc fix. Can you add a note to the whatsnew?

[mikofski]

Hi @wholmgren , I added a somewhat verbose note in "whats new for v0.4.5" b/c I wanted it to be absolutely clear that this docstring change re: units of pressure in the low-level spa.py module should have no effect on almost all users.

Update docstring in pvlib.spa.solar_position - change units of pressure to millibars. NOTE: units of pressure in pvlib.solar_position.spa_python and pvlib.solar_position.spa_c are still Pascals. This update should have no effect on most users, since it only applies to the low-level spa.py module.

[wholmgren]

thanks mark