star.app {leafSTAR}

Calculate the silhouette to area ratio from 'Ahmes' 1.0

Description

This is a version of star() function that only works with the output of 'Ahmes' 1.0. This function calculates the percentage of potential exposure of flat, tilted surfaces to direct solar radiation. It is equivalent to the ratio of the surface projected area to total surface area, but instead of using area data it uses spatial position angles (pitch, roll and course or tilt and course), geographical coordinates, hour and date information. This function implements equation 3 in Escribano-Rocafort et al. (2014).

Usage

star.app(x, lat, long, tz)

Arguments

x

Output of 'Ahmes' 1.0, a .csv file.

lat

A vector with the latitude of each observation in decimal format. If all observations correspond to the same latitude, lat can be introduced directly as a single number (see examples).

long

A vector with the longitude of each observation in decimal format. If all observations correspond to the same longitude, long can be introduced directly as a single number (see examples).

tz

A vector with the time zone of each observation. If all observations correspond to the same time zone, tz can be introduced directly as a single number. Time zones located at the West of Greenwich are negative, and at the East are positive; e.g., for Colombia, tz = -5; for Reunion Island, tz = 4.

Details

This function calls fixfile internally before calculating STAR. However, it does not modify the original dataset. To have a permanent fixed version of the data, use new.file<-fixfile(your.data). If using new.file within the package, be aware that the argument Ahmes should be set to FALSE.

Author(s)

Agustina Ventre-Lespiaucq and Silvia Santamaria Bueno.

References

Escribano-Rocafort, A.G., Ventre-Lespiaucq, A.B., Granado-Yela, C., Lopez-Pintor, A., Delgado, J.A., Munoz, V., Dorado, G.A., Balaguer, L. (2014). Simplifying data acquisition in plant canopies- Measurements of leaf angles with a cell phone. Methods in Ecology and Evolution 5:132-140. doi:10.1111/2041-210X.12141.

See Also

fixfile, star, simu.star.app

Examples

data(olea)
  starapp_olea<-star.app(olea,lat=40,long=4,tz=2)

 ## Add results to the original dataset
  olea1<-fixfile(olea) ## Fix the original dataset
  olea2<-cbind(olea1,as.data.frame(starapp_olea))

#star.app()