Honeybee Cumulative Sky Error _ Reading Wrong Weather Station


I had some weird experience with the Cumulative Sky component in Honeybee, in which it was referring to the wrong weather file!!!
(important to note that this only applies to HB Cumulative Sky component, and not to the LB component for the same task).

So, my understanding is that the way HB Cumulative Sky component reads the weather file is that it is independent of what the .epw weather file is called (eg ITA_milano_linate_mn70.epw), but what matters is the weather station name inside the actual epw file.

But I think there is a small bug in the component in the way it reads the this weather station name. So, in my case, the station name inside the epw file starts with ‘MN70_’ and if I already have used the component before to create a cumulative sky for another location (somewhere in Africa) for which the weather station name also starts with ‘MN70_’, then the component will not overwrite the old ‘MN70’ sky folder with the new weather location. (My default location for the sky files is ‘C:\ladybug\skylib\cumulativeSkies’ and the HB version is 0.0.60)

This way even though when I input the weather file for Milan, my cumulative sky component uses the sky dome for a different location!!!

To solve this issue, I list two manual ways:

  1. Either empty the cumulative sky folder before running a new simulation

2. Edit the epw file and make sure the weather station name doesn’t start with a generic text string like ‘MN70_’ which can cause problems. I solved my problem by renaming it from ‘MN70_Milano_Linate’ to ‘Milano_Linate’.

I think it will be useful if this bug could be fixed inside the component itself.

Lastly, can’t thank you enough for all your amazing work!

Hi Mohammad, Thank you for reporting. This methodology assumes that no two weather files would have the same name and weather station number, which is theory should be correct. Can you share with me two weather files that have the same name? It is easy to modify the code to get this fixed.

Hi Mostapha,

Here are the two epw files.

Thanks for looking into this.

mw_lilongwe_meas.epw (1.65 MB)
ITA_milano_linate_mn70.epw (1.65 MB)