Performance

A benchmark can reveal how many route gradients can be calculated per second using different interpolation methods:

e = dem_lisbon()
r = lisbon_road_network
res = bench::mark(check = FALSE,
  bilinear = slope_raster(r, e),
  simple   = slope_raster(r, e, method = "simple")
)

res
#> # A tibble: 2 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 bilinear     21.2ms   21.8ms      45.5   17.89MB     33.1
#> 2 simple       18.3ms   18.7ms      53.0    1.88MB     35.4

That is approximately

round(res$`itr/sec` * nrow(r))
#> [1] 12335 14376

routes per second using bilinear and simple interpolation methods, respectively.

To go faster, you can chose the simple method to gain some speed at the expense of accuracy:

res2 = bench::mark(check = FALSE,
  bilinear = slope_raster(r, e, method = "bilinear"),
  simple   = slope_raster(r, e, method = "simple")
)

res2
#> # A tibble: 2 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 bilinear     21.7ms   22.7ms      44.2    1.73MB     29.5
#> 2 simple       18.8ms   19.3ms      50.8    1.81MB     39.1

round(res2$`itr/sec` * nrow(r))
#> [1] 11973 13764

Benchmarking slopes calculation

Performance