Create a Wea file from an EPW file using Ladybug SDK

karimdaw · December 11, 2021, 12:30am

Thanks @mostapha, yes that would make sense of course. I suppose I assumed the behavior would be similar to the honeybee gh plugin where the required input was “_wea” which also excepts an epw file.

I have been doing a little research, and I was having a hard time finding .wea files to replace .epw files. Is there a routine in the lb/hb libs that converts epw to a wea file? Or a good resource to find .wea files for free? cheers

mostapha · December 11, 2021, 5:17pm

Hi @karimdaw,

When recipes are loaded to plugins, they can use alias inputs and add support for additional inputs or add additional checks. In this case, the wea input in the Grasshopper plugin passes the input to this function which does the translation to wea file if needed. The recipe, under the hood, only accepts a wea file.

github.com

pollination/handlers-python/blob/7482b312053d0d27e9d6059892fae873861c6234/pollination_handlers/inputs/wea.py#L10-L47


      
          def wea_handler(wea_obj):
              """Translate a Wea object to a wea file.
          
                  Args:
                      wea_obj: Either a Wea python object or the path to a wea or an epw file.
                          In case the wea_obj is a path to wea file it will be returned as is.
                          For epw files they will be converted to an annual wea.
          
                  Returns:
                      str -- Path to a wea file.
              """
          
              if isinstance(wea_obj, str):
                  if not os.path.isfile(wea_obj):
                      raise ValueError('Invalid file path: %s' % wea_obj)
                  if wea_obj.lower().endswith('.wea'):
                      wea_file = wea_obj
                  elif wea_obj.lower().endswith('.epw'):
                      # translate epw to wea
                      wea = Wea.from_epw_file(wea_obj)

This file has been truncated. show original

If you see the handler that I shared above you see how to do it. For future reference here is how it can be done.

from ladybug.wea import Wea

wea = Wea.from_epw_file('path_to_epw_file')
wea_file = wea.write('path_to_wea_file')

Hope it helps!

karimdaw · December 12, 2021, 6:58pm

Thanks again @mostapha, very helpful as always. I’ll use the handler to deal with epws going forward.