## ----setup, include = FALSE---------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.width = 7,
  fig.height = 4,
  dev = "svglite",
  fig.ext = "svg"
)

## ----libraries, include = FALSE-----------------------------------------------
library(topocast)
library(terra)

## ----cost, fig.height = 3.2---------------------------------------------------
set.seed(1)
g <- rast(nrows = 80, ncols = 80, xmin = 0, xmax = 8000, ymin = 0, ymax = 8000,
          crs = "EPSG:32632")
elev <- setValues(g, 1000 + 500 * sin(crds(g)[, 1] / 1500))
prec <- 800 - 0.15 * elev + setValues(g, rnorm(ncell(g), 0, 15))

y <- as.matrix(prec, wide = TRUE)
x <- as.matrix(elev, wide = TRUE)
small <- window_regression(y, x, radius = 3)
large <- window_regression(y, x, radius = 15)

op <- par(mfrow = c(1, 2), mar = c(2, 2, 2, 4))
plot(setValues(elev, as.vector(t(small$slope[[1]]))), main = "slope, radius 3")
plot(setValues(elev, as.vector(t(large$slope[[1]]))), main = "slope, radius 15")
par(op)