TrenchR (version 1.1.1)

proportion_silhouette_area: Organism Silhouette Area

Description

The function estimates the projected (silhouette) area as a portion of the surface area of the organism as a function of zenith angle. The function is useful for estimating absorbed solar radiation.

Usage

proportion_silhouette_area(psi, taxon, raz = 0, posture = "prostrate")

Value

numeric silhouette area as a proportion.

Arguments

psi

numeric zenith angle in degrees between 0 and 360.

taxon

character organism name. Current choices are "lizard", "frog", and "grasshopper".

raz

numeric relative solar azimuth angle (in degrees). Required if taxon = "lizard". This is the horizontal angle of the sun relative to the head and frontal plane of the lizard and options currently include 0 (in front), 90 (to side), and 180 (behind) degrees.

posture

character value describing posture. Required if taxon = "lizard". Options include "prostrate" (default) and "elevated".

Details

Relationships come from

• Lizards: Muth1977;textualTrenchR

• Frogs: Tracy1976;textualTrenchR

• Grasshoppers: Anderson1979;textualTrenchR

References

See Also

Other allometric functions: mass_from_length(), proportion_silhouette_area_shapes(), surface_area_from_length(), surface_area_from_mass(), surface_area_from_volume(), volume_from_length()

Examples

  proportion_silhouette_area(psi     = 60,   
                             taxon = "frog")
  proportion_silhouette_area(psi     = 60, 
                             taxon = "grasshopper")
  proportion_silhouette_area(psi       = 60, 
                             taxon   = "lizard", 
                             posture = "prostrate", 
                             raz     = 90)
  proportion_silhouette_area(psi       = 60, 
                             taxon   = "lizard", 
                             posture = "elevated", 
                             raz     = 180)