Get rectilinearity

Calculate rectilinearity - a measure of how well a shape fits a rectangle after optimal rotation.

Usage

get_rectilinearity(x, ..., .cols = NULL)

Arguments

x

A matrix (nx2), list of matrices, or tibble with coo columns.

...

Additional arguments (reserved for future use).

.cols

Column name(s) to process when x is a tibble. If NULL, automatically detects columns containing coo objects.

Value

• If x is a single matrix: returns a numeric scalar

• If x is a list: returns a numeric vector

• If x is a tibble: returns a numeric vector extracted from coo column

Details

Rectilinearity measures how rectangular a shape is by testing multiple rotations and finding the orientation that best fits a rectangle.

Algorithm from Zunic & Rosin (2003). Higher values indicate more rectangular shapes. Computationally intensive - tests 4n rotations where n is the number of points.

References

Zunic, J., & Rosin, P. L. (2003). Rectilinearity measurements for polygons. IEEE Transactions on Pattern Analysis and Machine Intelligence.

Examples

get_rectilinearity(shapes$cat)
#> [1] 0.1343944

# Use in measure() on mini bot for the sake of speed
bot[1:2, ] %>% measure("rectilinearity")
#> # A tibble: 2 × 6
#>   id     coo       type   fake  price coo_rectilinearity
#>   <chr>  <out>     <fct>  <fct> <dbl>              <dbl>
#> 1 brahma (138 x 2) whisky a       3                0.430
#> 2 caney  (168 x 2) whisky a       1.2              0.459