Calculate the distance between a pair of spatial boundaries

## Arguments

- x, y
Objects of the class

`slendr`

- measure
How to measure distance? This can be either

`'border'`

(distance between the borders of`x`

and`y`

) or`'center'`

(distance between their centroids).- time
Time closest to the spatial maps of

`x`

and`y`

if they represent`slendr_pop`

population boundaries (ignored for general`slendr_region`

objects)

## Value

If the coordinate reference system was specified, a distance in projected units (i.e. meters) is returned. Otherwise the function returns a normal Euclidean distance.

## Examples

```
# create two regions on a blank abstract landscape
region_a <- region("A", center = c(20, 50), radius = 20)
region_b <- region("B", center = c(80, 50), radius = 20)
plot_map(region_a, region_b)
# compute the distance between the centers of both population ranges
distance(region_a, region_b, measure = "center")
#> [1] 60
# compute the distance between the borders of both population ranges
distance(region_a, region_b, measure = "border")
#> [1] 20
```