# scale_vec_length_to_mm: Scale length of vector to given mm In markheckmann/dissertation: Functions used in dissertation

## Description

This function will scale a vector in usr coordinates to mm so the plotted length will be as desired. This will be particularly useful in situtations where the plot aspect ratio is unequal to 1.

## Usage

 `1` ```scale_vec_length_to_mm(v, mm = 10) ```

## Arguments

 `v` A 2D vector `mm` Numeric. Length to standardize vector to in mm.

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21``` ```par(mfrow=c(1,2)) plot(NULL, xlim=c(-1,1), ylim=c(-1,1), asp=2, main="vectors plot length\n varies by direction") rs <- seq(0, 2*pi, length=41) v = c(1,0) for (r in rs) { R = rotation_matrix_2d(r, clockwise = F) n = v %*% R segments(0,0, n, n) } plot(NULL, xlim=c(-1,1), ylim=c(-1,1), asp=2, main="vectors have 10mm plot\nlength in all directions") for (r in rs) { R = rotation_matrix_2d(r, clockwise = F) n = v %*% R b = scale_vec_length_to_mm(n, mm=10) segments(0,0, b, b) } ```

markheckmann/dissertation documentation built on May 21, 2019, 12:06 p.m.