High-resolution sky patch

HSK · February 4, 2025, 1:58am

Hello everyone,

I am trying to create a high-resolution sky patch (and its values) with a finer resolution than the Reinhart Sky, using 10-minute intervals.
As shown below, there are additional options, such as 2,305 sky patches, which can be generated using the density parameter. This parameter seems to be hardcoded in the SkyMatrix object of ladybug_radiance.

Could you help me generate a high-resolution sky patch?

Thanks

devang · February 4, 2025, 2:21am

Hi Hyoungsub,

thanks for posting. Copying @mikkel who can look into this.

mikkel · February 4, 2025, 12:22pm

Hi @HSK,

You are right that the parameter is hardcoded in ladybug-radiance. You can either get the default patches or 2305 patches – you cannot go higher like in honeybee-radiance. I will let @chris decide if he wants to remove this restriction in ladybug-radiance.

To generate the hoys for the 10-minute interval you can use the LB Analysis Period component and set the timestep to 6.

HSK · February 4, 2025, 2:02pm

Thank you @mikkel and @devang.
@mikkel Could you explain how to set up 2305 patches in the latest LB development version?

mikkel · February 4, 2025, 2:23pm

Hi @HSK,

Sorry – you cannot get 2305 patches, but only 577 patches by setting the high density to True. I didn’t pay attention when reading the documentation of the LB Cumulative Sky Matrix component, and just saw the number 4 in “… roughly 4 times …”, which equals 2305 patches in Radiance.

chris · July 8, 2025, 8:07pm

Sorry that I missed seeing this a few months back. I didn’t realize that the gendaymtx -m option can take any positive integer but it seems that you are right.

In that case, I’m ok with adding support for higher numbers of integers but I think it may be a while before we can get around to it given everything else that is on our plate right now. Granted, if you wanted to hack it, it might not be a huge effort to change it in the core libraries. You would have to change all of the lines like this in ladybug-radiance:

github.com

ladybug-tools/ladybug-radiance/blob/master/ladybug_radiance/skymatrix.py#L551


      
          def _run_gendaymtx(self, wea_file, wea_duration):
              """Run a Wea file through gendaymtx and get direct and diffuse radiation.
          
              Args:
                  wea_file: Path to a Wea file to be run through gendaymtx.
                  wea_duration: Number for the duration of the Wea in hours. This is used
                      to convert between the average value output by the command and the
                      cumulative value that is needed for all ladybug analyses.
              """
              assert GENDAYMTX_EXE is not None, 'No Radiance installation was found.'
              density = 2 if self.high_density else 1
              use_shell = True if os.name == 'nt' else False
              # command for direct patches
              cmds = [GENDAYMTX_EXE, '-m', str(density), '-d', '-O1', '-A', wea_file]
              process = subprocess.Popen(cmds, stdout=subprocess.PIPE, shell=use_shell)
              stdout = process.communicate()
              dir_data_str = stdout[0]
              # command for diffuse patches
              cmds = [GENDAYMTX_EXE, '-m', str(density), '-s', '-O1', '-A', wea_file]
              process = subprocess.Popen(cmds, stdout=subprocess.PIPE, shell=use_shell)
              stdout = process.communicate()

… and change all of the places that use the ladybug view_sphere like this:

github.com

ladybug-tools/ladybug-radiance/blob/master/ladybug_radiance/skymatrix.py#L61-L68


      
          PATCHES_PER_ROW = {
              1: view_sphere.TREGENZA_PATCHES_PER_ROW + (1,),
              2: view_sphere.REINHART_PATCHES_PER_ROW + (1,)
          }
          PATCH_ROW_COEFF = {
              1: view_sphere.TREGENZA_COEFFICIENTS,
              2: view_sphere.REINHART_COEFFICIENTS
          }

But there are a lot of ladybug-grasshopper components that would then need to be updated if we wanted to add official support for this. So, if you don’t want to hack it on your own, you may need to be patient.