pvlib.bifacial.utils.vf_ground_sky_2d(rotation, gcr, x, pitch, height, max_rows=10)[source]#

Calculate the fraction of the sky dome visible from point x on the ground.

The view factor accounts for the obstruction of the sky by array rows that are assumed to be infinitely long. View factors are thus calculated in a 2D geometry. The ground is assumed to be flat and level.

  • rotation (numeric) – Rotation angle of the row’s right edge relative to row center. [degree]

  • gcr (float) – Ratio of the row slant length to the row spacing (pitch). [unitless]

  • x (numeric) – Position on the ground between two rows, as a fraction of the pitch. x = 0 corresponds to the point on the ground directly below the center point of a row. Positive x is towards the right. [unitless]

  • height (float) – Height of the center point of the row above the ground; must be in the same units as pitch.

  • pitch (float) – Distance between two rows; must be in the same units as height.

  • max_rows (int, default 10) – Maximum number of rows to consider on either side of the current row. [unitless]


vf (array) – Fraction of sky dome visible from each point on the ground. Shape is (len(x), len(rotation)). [unitless]