Sky View Factor — terr_sky_view • fieldClim

Calculates the sky view factor, which represents how much sky can be seen from a given point.

Usage

terr_sky_view(...)

# Default S3 method
terr_sky_view(slope, valley, ...)

# S3 method for class 'weather_station'
terr_sky_view(weather_station, ...)

Arguments

...: Additional arguments passed to other methods.
slope: Slope of the terrain in degrees.
valley: Logical value indicating if the location is in a valley (TRUE) or not (FALSE).
weather_station: A weather_station object.

Value

Ratio from 0 to 1, unitless, representing the sky view factor.

Details

The sky view factor ($SVF$) is calculated as: $$SVF = \frac{1 + \cos(\theta)}{2}$$ for non-valley locations, and $$SVF = \cos(\theta)$$ for valley locations, where $\theta$ is the slope angle.

The terrain view factor can be calculated by 1 - terr_sky_view(), which represents how much terrain can be seen from the point.

References

Bendix 2004, p. 63 eq. 3.15.

Examples

# Sky view factor for a slope of 30 degrees not in a valley
terr_sky_view(slope = 30, valley = FALSE)
#> [1] 0.9330127

# Sky view factor for a slope of 30 degrees in a valley
terr_sky_view(slope = 30, valley = TRUE)
#> [1] 0.8660254