## ----include = FALSE----------------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

## ----eval=FALSE---------------------------------------------------------------
# # install.packages("remotes")
# remotes::install_github("ropensci/slopes")

## ----eval=FALSE---------------------------------------------------------------
# # install.packages("remotes")
# remotes::install_github("ropensci/slopes", dependencies = "Suggests")

## ----eval=FALSE---------------------------------------------------------------
# usethis::edit_r_environ()
# # Then add the following line to the file that opens:
# # MAPBOX_API_KEY=xxxxx # replace XXX with your api key

## -----------------------------------------------------------------------------
library(slopes)
library(sf)

# Load example data
data(lisbon_route)
dem_lisbon <- dem_lisbon()

## -----------------------------------------------------------------------------
sf_linestring_xyz_local <- elevation_add(lisbon_route, dem = dem_lisbon)
head(sf::st_coordinates(sf_linestring_xyz_local))

## ----eval=FALSE---------------------------------------------------------------
# # Requires a MapBox API key and the ceramic package
# # sf_linestring_xyz_mapbox = elevation_add(lisbon_route)
# # head(sf::st_coordinates(sf_linestring_xyz_mapbox))

## -----------------------------------------------------------------------------
slope <- slope_xyz(sf_linestring_xyz_local)
slope

## -----------------------------------------------------------------------------
# ensure a palette and breaks exist
brks <- c(3, 6, 10, 20, 40, 100)
pal <- slopes_palette(length(brks) - 1)

plot_slope(sf_linestring_xyz_local, pal = pal, brks = brks)

## -----------------------------------------------------------------------------
lisbon_route_xyz <- elevation_add(lisbon_route, dem = dem_lisbon())
lisbon_route_segments_xyz <- route_to_segments(lisbon_route_xyz)
lisbon_route_segments_xyz$slope <- slope_xyz(lisbon_route_segments_xyz)
summary(lisbon_route_segments_xyz$slope)

## -----------------------------------------------------------------------------
plot(st_geometry(lisbon_route_segments_xyz),
  col = heat.colors(length(lisbon_route_segments_xyz$slope))[rank(lisbon_route_segments_xyz$slope)],
  lwd = 3, main = "Slope by vertex segments"
)

## ----warning=FALSE------------------------------------------------------------
lisbon_route_100m <- stplanr::line_segment(lisbon_route, segment_length = 100)
lisbon_route_100m_xyz <- elevation_add(lisbon_route_100m, dem = dem_lisbon())
lisbon_route_100m_xyz$slope <- slope_xyz(lisbon_route_100m_xyz)
summary(lisbon_route_100m_xyz$slope)

## -----------------------------------------------------------------------------
plot(st_geometry(lisbon_route_100m_xyz),
  col = heat.colors(length(lisbon_route_100m_xyz$slope))[rank(lisbon_route_100m_xyz$slope)],
  lwd = 3, main = "Slope by 100 m segments"
)