docs: def getCatalogPixels(self):
          """
          Return the catalog pixels spanned by this ROI.
          """
          filenames = self.config.getFilenames()
  
          nside_catalog = self.config.params['coords']['nside_catalog']
          nside_pixel = self.config.params['coords']['nside_pixel']
          # All possible catalog pixels spanned by the ROI
          superpix = ugali.utils.skymap.superpixel(self.pixels,nside_pixel,nside_catalog)
          superpix = np.unique(superpix)
          # Only catalog pixels that exist in catalog files
          pixels = np.intersect1d(superpix, filenames['pix'].compressed())
          return pixels