Source code for

"""Generate sky with certain irradiance."""
from __future__ import division
import argparse
import shlex

import honeybee.typing as typing
import ladybug.futil as futil

from ._skybase import _PointInTime

[docs]class CertainIrradiance(_PointInTime): """sky with certain irradiance. The output of CertainIrradiance sky is similar to using command below:: gensky -c -B desired_irradiance You can also generate the sky with certain illuminance using ``from_illuminance`` classmethod. The method converts the illuminance value to irradiance by dividing it by 179.0:: gensky -c -B [desired_illuminance / 179.0] It also includes ground glow source. Ground reflectance is set to %20 by default which is gensky's default value. Use `ground_reflectance` property to adjust this value. Note: The conversion factor in the Radiance system for luminous efficacy is fixed at KR= 179 lumens/watt (lm/w). This should not be confused with the more usual daylighting value, which can be anywhere between 50 and 150 lm/w depending on the type of sky or light considered. For more information see links below on the Radiance forum: * * Default value is set to 558.659 which corresponds to a sky with 100,000 lux horizontal illuminance. Args: irradiance: Desired horizontal diffuse irradiance value in watts/meter2 (Default: 558.659). ground_reflectance: Average ground reflectance (Default: 0.2). uniform: Boolean to note whether the sky is uniform instead of cloudy. (Default: False) Properties: * irradiance * illuminance * ground_hemisphere * sky_hemisphere * ground_reflectance * uniform * is_point_in_time * is_climate_based """ __slots__ = ('_irradiance', '_uniform') def __init__(self, irradiance=558.659, ground_reflectance=0.2, uniform=False): """Create sky with certain irradiance.""" _PointInTime.__init__(self, ground_reflectance) self.irradiance = irradiance self.uniform = uniform
[docs] @classmethod def from_illuminance(cls, illuminance=100000, ground_reflectance=0.2, uniform=False): """Create sky with certain illuminance. Args: illuminance: Desired horizontal illuminance value in lux (Default: 100000). ground_reflectance: Average ground reflectance (Default: 0.2). uniform: Boolean to note whether the sky is uniform instead of cloudy. (Default: False) """ return cls(illuminance / 179.0, ground_reflectance, uniform)
@property def irradiance(self): """Sky irradiance value.""" return self._irradiance @irradiance.setter def irradiance(self, irradiance): self._irradiance = typing.float_positive(irradiance) \ if irradiance is not None else 558.659 @property def illuminance(self): """Sky illuminance value.""" return round(self._irradiance * 179.0, 2) @property def uniform(self): """Boolean to note whether the sky is uniform instead of cloudy.""" return self._uniform @uniform.setter def uniform(self, value): self._uniform = bool(value) @property def is_point_in_time(self): """Return True if the sky is generated for a single point in time.""" return False
[docs] @classmethod def from_dict(cls, data): """Create the sky from a dictionary. Args: data: A python dictionary in the following format .. code-block:: python { 'type': 'CertainIrradiance', 'irradiance': 558.659, 'ground_reflectance': 0.2, 'uniform': False } """ assert 'type' in data, \ 'Input dict is missing type. Not a valid CertainIrradiance dictionary.' assert data['type'] == 'CertainIrradiance', \ 'Input type must be CertainIrradiance not %s' % data['type'] uniform = data['uniform'] if 'uniform' in data else False gr = data['ground_reflectance'] if 'ground_reflectance' in data else 0.2 return cls(data['irradiance'], gr, uniform)
[docs] @classmethod def from_string(cls, sky_string): """Create a CertainIrradiance sky from a string. Args: sky_string: A text string representing a CertainIrradiance sky. This can be either a string with a certain irradiance (eg. "irradiance 558.659") or with a certain illuminance (eg. "illuminance 100000"). Any sky string can optionally have a "-g" property of a fractional number, which sets the reflectance of the ground. If unspecified, the ground will have a reflectance of 0.2. This sky can also have a "-u" property to set the sky as uniform instead of the default cloudy. Usage: .. code-block:: python # irradiance string representation of the sky sky_string = "irradiance 558.659" sky = CertainIrradiance.from_string(sky_string) # illuminance string representation of the sky sky_string = "illuminance 100000 -g 0.3 -u" sky = CertainIrradiance.from_string(sky_string) """ # check the input lower_str = sky_string.lower() assert lower_str.startswith(('irradiance', 'illuminance')), \ 'Expected string representation of CertainIrradiance sky "{}" to ' \ 'start with "irradiance" or "illuminance".'.format(sky_string) split_str = shlex.split(lower_str) # make a parser for all of the other sky properties pars = argparse.ArgumentParser() pars.add_argument('value', action='store', type=float) pars.add_argument('-g', action='store', dest='g', type=float, default=0.2) pars.add_argument('-u', action='store_true', dest='u', default=False) props = pars.parse_args(split_str[1:]) # create the sky object if split_str[0] == 'irradiance': return cls(props.value, props.g, props.u) else: return cls.from_illuminance(props.value, props.g, props.u)
[docs] def to_radiance(self): """Return radiance definition as a string.""" sky_type = '-u' if self.uniform else '-c' command = '!gensky -ang 45 0 %s -B %.6f -g %.3f' % ( sky_type, self.irradiance, self.ground_reflectance ) return '%s\n\n%s\n\n%s\n' % ( command, self.sky_hemisphere, self.ground_hemisphere )
[docs] def to_dict(self): """Translate sky to a dictionary.""" return { 'type': 'CertainIrradiance', 'irradiance': self.irradiance, 'ground_reflectance': self.ground_reflectance, 'uniform': self.uniform }
[docs] def to_file(self, folder, name=None, mkdir=False): """Write sky hemisphere to a sky_hemisphere.rad Radiance file. Args: folder: Target folder. name: File name. mkdir: A boolean to note if the directory should be created if doesn't exist (default: False). Returns: Full path to the newly created file. """ content = self.to_radiance() name = typing.valid_string(name) if name \ else '' % int(self.illuminance) return futil.write_to_file_by_name(folder, name, content, mkdir)
def __eq__(self, value): if type(value) != type(self) \ or value.irradiance != self.irradiance \ or self.ground_reflectance != value.ground_reflectance \ or self.ground_hemisphere != value.ground_hemisphere \ or self.sky_hemisphere != value.sky_hemisphere: return False return True def __ne__(self, value): return not self.__eq__(value) def __repr__(self): """Sky representation.""" base_str = 'irradiance {} -g {}'.format(self.irradiance, self.ground_reflectance) return base_str + ' -u' if self.uniform else base_str