calcLAD function

Calculate summary statistics from measured leaf inclination angles

The function derives summary statistics from measured leaf inclination angles:.

• Mean (MTA), standard deviation (SD) and frequency (NR) observations.
• The two (mu, nu) Beta parameters derived from the formula provided by Goel and Strebel (1984) tools:::Rd_expr_doi("10.2134/agronj1984.00021962007600050021x") .
• The distribution type, comparing the distribution against the six theoretical LAD distributions provided by de Wit (1965).

Arguments

• data: Dataframe. The dataframe containing leaf inclination angle measurements.
• angles: Numeric. The column containing leaf inclination angle measurements (in degrees).
• type: Character. If set to "summary", it gives summary distributions. If set to "extended", it calculates LAD probability density (pdf) and G-function (G) for view or inclination angles (theta). Default set to "summary".
• ...: The column(s) indicating the grouping variables to be considered for calculating summary statistics.

Returns

A dataframe with the grouping variable(s), and:

• summary statistics (MTA, SD, N, mu, nu, distribution) in case of type="summary";
• LAD (pdf) and G-function (G) in case of type="extended".

Examples

head(Chianucci)

calcLAD(Chianucci,Angle_degree,type='summary',Genus,Species)
calcLAD(Chianucci,Angle_degree,type='extended',Genus,Species)