Calculate minimum distance between multiple polygons with R

Question

I'm still somewhat new to R and the sf package...

I have two sets of multipolygon data that I am trying to analyze. My first set of polygons (fires) contains hundreds of wildfire perimeters. The second set (towns) contains hundreds of urban areas boundaries.

For each fire, I would like to calculate the distance to the closest town (fire polygon edge to closest town polygon edge), and add that as a field to each fire.

So far I have mostly been using the sf package for spatial data. In my searches, I can only find minimum distance methods for polygons to points, points to points, lines to points, etc. but cannot seem to find polygon to polygon examples. Any help to send me in the right direction would be much appreciated! Thank you.

Answer 1

@TimSalabim Thank you for sending me in the right direction. I was able to accomplish what I was after. Maybe not the most elegant solution, but it worked.

# create an index of the nearest feature
index <- st_nearest_feature(x = poly1, y = poly2)

# slice based on the index
poly2 <- poly2 %>% slice(index)

# calculate distance between polygons
poly_dist <- st_distance(x = poly1, y= poly2, by_element = TRUE)

# add the distance calculations to the fire polygons
poly1$distance <- poly_dist