LW1949 (version 1.1.0)

nomoCoord: Find the Coordinate from the Scale of a Nomograph

Description

Find the x and y coordinate corresponding to a specified point on a nomograph scale.

Usage

nomoCoord(df, val)

Arguments

df

A data frame with three columns, the x and y coordinates of the nomograph scale and the corresponding values.

val

A numeric scalar identifying the point on the scale for which the coordinates will be returned.

Value

A numeric vector of length two with the x and y coordinates of the specified point in plotting units of the nomograph.

Details

The function makes it easier to add points or lines to a nomograph for illustrative purposes. Each scale is assumed to be displayed on the log10 scale.

Examples

scales <- LWnomo1(TRUE)
fromxy <- nomoCoord(scales$scale1r, 34)
toxy <- nomoCoord(scales$scale3, 16^2/(100*34))
segments(fromxy[1], fromxy[2], toxy[1], toxy[2], col="red")