From af3a7b8b0abfb04a13431d54e3e3d501faf04564 Mon Sep 17 00:00:00 2001
From: RFlx <temospena@gmail.com>
Date: Mon, 22 Jun 2026 13:43:55 +0100
Subject: [PATCH 1/4] extend elevation_add to support point geometries with
 configurable Z-coordinate embedding and elevation columns #21

---
 R/slopes.R               | 103 ++++++++++++++++++++++++++++++++-------
 man/elevation_add.Rd     |  63 +++++++++++++++++++-----
 man/route_to_segments.Rd |   6 +--
 3 files changed, 139 insertions(+), 33 deletions(-)

diff --git a/R/slopes.R b/R/slopes.R
index a6b3934..2cb5b59 100644
--- a/R/slopes.R
+++ b/R/slopes.R
@@ -230,42 +230,110 @@ elevation_extract <- function(m, dem, method = "bilinear", terra = NULL) {
   terra::extract(dem, m[, 1:2], method = method)[[1]]
 }
 
-#' Add elevation data to route linestrings
+#' Add elevation data to routes linestrings or points
 #'
-#' Adds elevation (Z) coordinates to linestring geometries using DEM data.
+#' Adds elevation data to sf objects using a digital elevation model (DEM).
 #'
-#' @param routes An sf object containing linestring geometries
-#' @param dem A SpatRaster object containing elevation data (default: NULL for automatic download)
-#' @param method Method for raster extraction (default: "bilinear")
+#' For **linestring** geometries, the function attaches elevation as the Z
+#' coordinate of each vertex, returning an XYZ linestring sf object.
+#'
+#' For **point** geometries, the function embeds the Z coordinate directly in
+#' the geometry by default (returning POINT Z features), consistent with the
+#' linestring behaviour. An `elevation` column can additionally be added by
+#' setting `add_column = TRUE`.
+#'
+#' @param routes An sf object containing linestring or point geometries.
+#' @param dem A SpatRaster object containing elevation data
+#'   (default: `NULL` for automatic download via `elevation_get()`).
+#' @param method Method for raster extraction (default: `"bilinear"`).
+#' @param add_z For **point** geometries only: if `TRUE` (the default), the Z
+#'   coordinate is embedded directly in the point geometry, returning POINT Z
+#'   features. Set to `FALSE` to keep the original XY geometry. Ignored for
+#'   linestrings (Z is always added to linestring vertices).
+#' @param add_column For **point** geometries only: if `TRUE`, an `elevation`
+#'   column is added to the returned sf object in addition to (or instead of,
+#'   when `add_z = FALSE`) the Z geometry. Default: `FALSE`. Ignored for
+#'   linestrings.
 #' @param terra Deprecated. Ignored; terra is always used.
-#' @return An sf object with XYZ linestring geometries
+#' @return An sf object. For linestrings: XYZ linestring geometries. For points:
+#'   POINT Z geometry (when `add_z = TRUE`) and/or an `elevation` column (when
+#'   `add_column = TRUE`).
 #' @export
 #' @examples
 #' library(sf)
-#' routes = lisbon_road_network[204, ]
-#' dem = dem_lisbon()
-#' (r3d = elevation_add(routes, dem))
-#' st_z_range(routes)
+#' # Linestring usage:
+#' routes <- lisbon_road_network[204, ]
+#' dem <- dem_lisbon()
+#' (r3d <- elevation_add(routes, dem))
 #' st_z_range(r3d)
 #' plot(st_coordinates(r3d)[, 3])
 #' plot_slope(r3d)
+#' # Point usage — Z embedded in geometry by default:
+#' pts <- sf::st_cast(sf::st_geometry(lisbon_road_network[204, ]), "POINT")
+#' pts <- sf::st_sf(id = seq_along(pts), geometry = pts)
+#' (pts_z <- elevation_add(pts, dem))
+#' sf::st_z_range(pts_z)
+#' # Also add an elevation column:
+#' (pts_z_col <- elevation_add(pts, dem, add_column = TRUE))
+#' pts_z_col$elevation
+#' # Only an elevation column, keep XY geometry:
+#' (pts_col <- elevation_add(pts, dem, add_z = FALSE, add_column = TRUE))
 #' \dontrun{
 #' # Get elevation data (requires internet connection, ceramic pkg, and API key):
 #' if (requireNamespace("ceramic", quietly = TRUE)) {
-#'   r3d_get = elevation_add(cyclestreets_route)
+#'   r3d_get <- elevation_add(cyclestreets_route)
 #'   plot_slope(r3d_get)
 #' }
 #' }
-elevation_add <- function(routes, dem = NULL, method = "bilinear", terra = NULL) {
+elevation_add <- function(routes, dem = NULL, method = "bilinear",
+                          add_z = TRUE, add_column = FALSE,
+                          terra = NULL) {
   if (!is.null(terra)) {
     .Deprecated(msg = "The 'terra' argument is deprecated and ignored. terra is always used.")
   }
   stopifnotsf(routes)
+
+  geom_types <- unique(sf::st_geometry_type(routes))
+
+  # ── POINT branch ────────────────────────────────────────────────────────────
+  if (all(geom_types %in% c("POINT", "MULTIPOINT"))) {
+    if (is.null(dem)) {
+      dem <- elevation_get(routes)
+      r_original <- routes
+      routes <- sf::st_transform(routes, terra::crs(dem))
+      suppressWarnings({
+        sf::st_crs(routes) <- sf::st_crs(r_original)
+      })
+      m <- sf::st_coordinates(routes)
+      mo <- sf::st_coordinates(r_original)
+      z <- as.numeric(elevation_extract(m, dem, method = method))
+      routes <- r_original # restore original CRS / coords
+    } else {
+      m <- sf::st_coordinates(routes)
+      z <- as.numeric(elevation_extract(m, dem, method = method))
+      mo <- m
+    }
+    if (add_column) {
+      routes$elevation <- z
+    }
+    if (add_z) {
+      m_xyz <- cbind(mo[, 1:2], z)
+      points_z <- lapply(seq_len(nrow(m_xyz)), function(i) {
+        sf::st_point(m_xyz[i, ], dim = "XYZ")
+      })
+      sf::st_geometry(routes) <- sf::st_sfc(points_z, crs = sf::st_crs(routes))
+    }
+    return(routes)
+  }
+
+  # ── LINESTRING branch ────────────────────────────────────────────────────────
   if (is.null(dem)) {
-    dem <- elevation_get(routes)  # returns SpatRaster
+    dem <- elevation_get(routes) # returns SpatRaster
     r_original <- routes
     routes <- sf::st_transform(routes, terra::crs(dem))
-    suppressWarnings({sf::st_crs(routes) <- sf::st_crs(r_original)})
+    suppressWarnings({
+      sf::st_crs(routes) <- sf::st_crs(r_original)
+    })
     m <- sf::st_coordinates(routes)
     mo <- sf::st_coordinates(r_original)
     z <- as.numeric(elevation_extract(m, dem, method = method))
@@ -299,9 +367,9 @@ stopifnotsf <- function(x, arg_name = "routes") if (!methods::is(x, "sf")) stop(
 #' @return An sf object with one LINESTRING feature per vertex-to-vertex segment.
 #' @export
 #' @examples
-#' route_xyz = elevation_add(lisbon_route, dem = dem_lisbon())
-#' segs = route_to_segments(route_xyz)
-#' segs$slope = slope_xyz(segs)
+#' route_xyz <- elevation_add(lisbon_route, dem = dem_lisbon())
+#' segs <- route_to_segments(route_xyz)
+#' segs$slope <- slope_xyz(segs)
 #' summary(segs$slope)
 route_to_segments <- function(route_xyz) {
   coords <- sf::st_coordinates(route_xyz)
@@ -309,4 +377,3 @@ route_to_segments <- function(route_xyz) {
   segs <- lapply(seq_len(n - 1), function(i) sf::st_linestring(coords[i:(i + 1), 1:3]))
   sf::st_sf(geometry = sf::st_sfc(segs, crs = sf::st_crs(route_xyz)))
 }
-
diff --git a/man/elevation_add.Rd b/man/elevation_add.Rd
index 2e3b863..b2efeea 100644
--- a/man/elevation_add.Rd
+++ b/man/elevation_add.Rd
@@ -2,38 +2,77 @@
 % Please edit documentation in R/slopes.R
 \name{elevation_add}
 \alias{elevation_add}
-\title{Add elevation data to route linestrings}
+\title{Add elevation data to routes linestrings or points}
 \usage{
-elevation_add(routes, dem = NULL, method = "bilinear", terra = NULL)
+elevation_add(
+  routes,
+  dem = NULL,
+  method = "bilinear",
+  add_z = TRUE,
+  add_column = FALSE,
+  terra = NULL
+)
 }
 \arguments{
-\item{routes}{An sf object containing linestring geometries}
+\item{routes}{An sf object containing linestring or point geometries.}
 
-\item{dem}{A SpatRaster object containing elevation data (default: NULL for automatic download)}
+\item{dem}{A SpatRaster object containing elevation data
+(default: \code{NULL} for automatic download via \code{elevation_get()}).}
 
-\item{method}{Method for raster extraction (default: "bilinear")}
+\item{method}{Method for raster extraction (default: \code{"bilinear"}).}
+
+\item{add_z}{For \strong{point} geometries only: if \code{TRUE} (the default), the Z
+coordinate is embedded directly in the point geometry, returning POINT Z
+features. Set to \code{FALSE} to keep the original XY geometry. Ignored for
+linestrings (Z is always added to linestring vertices).}
+
+\item{add_column}{For \strong{point} geometries only: if \code{TRUE}, an \code{elevation}
+column is added to the returned sf object in addition to (or instead of,
+when \code{add_z = FALSE}) the Z geometry. Default: \code{FALSE}. Ignored for
+linestrings.}
 
 \item{terra}{Deprecated. Ignored; terra is always used.}
 }
 \value{
-An sf object with XYZ linestring geometries
+An sf object. For linestrings: XYZ linestring geometries. For points:
+POINT Z geometry (when \code{add_z = TRUE}) and/or an \code{elevation} column (when
+\code{add_column = TRUE}).
 }
 \description{
-Adds elevation (Z) coordinates to linestring geometries using DEM data.
+Adds elevation data to sf objects using a digital elevation model (DEM).
+}
+\details{
+For \strong{linestring} geometries, the function attaches elevation as the Z
+coordinate of each vertex, returning an XYZ linestring sf object.
+
+For \strong{point} geometries, the function embeds the Z coordinate directly in
+the geometry by default (returning POINT Z features), consistent with the
+linestring behaviour. An \code{elevation} column can additionally be added by
+setting \code{add_column = TRUE}.
 }
 \examples{
 library(sf)
-routes = lisbon_road_network[204, ]
-dem = dem_lisbon()
-(r3d = elevation_add(routes, dem))
-st_z_range(routes)
+# Linestring usage:
+routes <- lisbon_road_network[204, ]
+dem <- dem_lisbon()
+(r3d <- elevation_add(routes, dem))
 st_z_range(r3d)
 plot(st_coordinates(r3d)[, 3])
 plot_slope(r3d)
+# Point usage — Z embedded in geometry by default:
+pts <- sf::st_cast(sf::st_geometry(lisbon_road_network[204, ]), "POINT")
+pts <- sf::st_sf(id = seq_along(pts), geometry = pts)
+(pts_z <- elevation_add(pts, dem))
+sf::st_z_range(pts_z)
+# Also add an elevation column:
+(pts_z_col <- elevation_add(pts, dem, add_column = TRUE))
+pts_z_col$elevation
+# Only an elevation column, keep XY geometry:
+(pts_col <- elevation_add(pts, dem, add_z = FALSE, add_column = TRUE))
 \dontrun{
 # Get elevation data (requires internet connection, ceramic pkg, and API key):
 if (requireNamespace("ceramic", quietly = TRUE)) {
-  r3d_get = elevation_add(cyclestreets_route)
+  r3d_get <- elevation_add(cyclestreets_route)
   plot_slope(r3d_get)
 }
 }
diff --git a/man/route_to_segments.Rd b/man/route_to_segments.Rd
index 3d9ab22..541aa7d 100644
--- a/man/route_to_segments.Rd
+++ b/man/route_to_segments.Rd
@@ -19,8 +19,8 @@ one per consecutive vertex pair. Useful for computing per-segment slopes
 with \code{\link[=slope_xyz]{slope_xyz()}}.
 }
 \examples{
-route_xyz = elevation_add(lisbon_route, dem = dem_lisbon())
-segs = route_to_segments(route_xyz)
-segs$slope = slope_xyz(segs)
+route_xyz <- elevation_add(lisbon_route, dem = dem_lisbon())
+segs <- route_to_segments(route_xyz)
+segs$slope <- slope_xyz(segs)
 summary(segs$slope)
 }

From 5ef3176e12fefffe2fcbcb278ed071d18d514ea1 Mon Sep 17 00:00:00 2001
From: RFlx <temospena@gmail.com>
Date: Mon, 22 Jun 2026 13:44:13 +0100
Subject: [PATCH 2/4] #21 add tests with elevation to points

---
 tests/testthat/Rplots.pdf    | Bin 3611 -> 3611 bytes
 tests/testthat/test-slopes.R |  37 +++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/tests/testthat/Rplots.pdf b/tests/testthat/Rplots.pdf
index 2835fe94d255fe17c60cb395fe98a73d1778ff8d..45f1c389d5edf9d04b31ed04cb16eebea237e73b 100644
GIT binary patch
delta 47
wcmbO&Gh1eYxr&jIp|P=rv8g7PzHfetOJYf?f`*Hgk%5t!ff-D0WAp)D04L21UjP6A

delta 47
wcmbO&Gh1eYxr(8gp}Dbvk&z~szHfetOJYf?f`*Hgk%5t!ff-D0WAp)D04FaDRR910

diff --git a/tests/testthat/test-slopes.R b/tests/testthat/test-slopes.R
index a763c4b..01a1f08 100644
--- a/tests/testthat/test-slopes.R
+++ b/tests/testthat/test-slopes.R
@@ -86,3 +86,40 @@ test_that("slope_* functions work", {
   expect_error(slopes:::stop_is_not_linestring(1))
 
 })
+
+test_that("elevation_add() works with POINT geometries", {
+  dem <- dem_lisbon()
+  pts <- sf::st_cast(sf::st_geometry(lisbon_road_network[204, ]), "POINT")
+  pts <- sf::st_sf(id = seq_along(pts), geometry = pts)
+
+  # Default: add_z = TRUE, no elevation column
+  pts_z <- elevation_add(pts, dem)
+  expect_s3_class(pts_z, "sf")
+  expect_equal(as.character(sf::st_geometry_type(pts_z)[1]), "POINT")
+  expect_true(!is.na(sf::st_z_range(pts_z)[1]))      # has Z coordinate
+  expect_false("elevation" %in% names(pts_z))
+  expect_equal(
+    sf::st_z_range(pts_z),
+    c(86, 92),
+    ignore_attr = TRUE,
+    tolerance = 10
+  )
+
+  # add_column = TRUE: Z in geometry AND elevation column
+  pts_z_col <- elevation_add(pts, dem, add_column = TRUE)
+  expect_true("elevation" %in% names(pts_z_col))
+  expect_true(!is.na(sf::st_z_range(pts_z_col)[1]))  # still has Z
+  expect_equal(
+    round(pts_z_col$elevation[1:3], 2),
+    c(92.31, 91.93, 91.60)
+  )
+
+  # add_z = FALSE, add_column = TRUE: XY geometry with elevation column
+  pts_col <- elevation_add(pts, dem, add_z = FALSE, add_column = TRUE)
+  expect_true("elevation" %in% names(pts_col))
+  expect_true(is.null(sf::st_z_range(pts_col)))      # XY: no Z coordinate
+  expect_equal(
+    round(pts_col$elevation[1:3], 2),
+    c(92.31, 91.93, 91.60)
+  )
+})

From e1a50ad74b71d9e83d4d48e2c0cf6ef2225f11cf Mon Sep 17 00:00:00 2001
From: RFlx <temospena@gmail.com>
Date: Mon, 22 Jun 2026 13:57:54 +0100
Subject: [PATCH 3/4] reorganize elevation functions in elevation.R module and
 update related tests

---
 R/elevation.R                   | 245 ++++++++++++++++++++++++++++++++
 R/slope_get.R                   |  44 +-----
 R/slopes.R                      | 149 +------------------
 R/z-functions.R                 |  32 -----
 tests/testthat/Rplots.pdf       | Bin 3611 -> 3611 bytes
 tests/testthat/test-elevation.R |  88 ++++++++++++
 tests/testthat/test-get.R       |   8 --
 tests/testthat/test-slopes.R    |  57 +-------
 tests/testthat/test-z.R         |  16 ---
 9 files changed, 336 insertions(+), 303 deletions(-)
 create mode 100644 R/elevation.R
 delete mode 100644 R/z-functions.R
 create mode 100644 tests/testthat/test-elevation.R
 delete mode 100644 tests/testthat/test-get.R
 delete mode 100644 tests/testthat/test-z.R

diff --git a/R/elevation.R b/R/elevation.R
new file mode 100644
index 0000000..52bbec3
--- /dev/null
+++ b/R/elevation.R
@@ -0,0 +1,245 @@
+# Elevation get/extract/add and Z helper functions
+
+# ── Z value helpers ─────────────────────────────────────────────────────────
+
+z_value <- function(x) {
+  coords <- sf::st_coordinates(x)
+  if ("Z" %in% colnames(coords)) {
+    return(coords[, "Z"])
+  } else {
+    stop("No Z coordinates found in the input data")
+  }
+}
+
+z_mean <- function(x) {
+  mean(z_value(x), na.rm = TRUE)
+}
+
+z_min <- function(x) {
+  min(z_value(x), na.rm = TRUE)
+}
+
+z_max <- function(x) {
+  max(z_value(x), na.rm = TRUE)
+}
+
+z_start <- function(x) {
+  z_vals <- z_value(x)
+  z_vals[1]
+}
+
+z_end <- function(x) {
+  z_vals <- z_value(x)
+  z_vals[length(z_vals)]
+}
+
+z_elevation_change_start_end <- function(x) {
+  z_end(x) - z_start(x)
+}
+
+z_direction <- function(x) {
+  sign(z_elevation_change_start_end(x))
+}
+
+z_cumulative_difference <- function(x) {
+  z <- z_value(x)
+  sum(abs(diff(z)), na.rm = TRUE)
+}
+
+# ── elevation_get ────────────────────────────────────────────────────────────
+
+#' Get elevation data for routes
+#'
+#' Downloads elevation data using the ceramic package for given routes.
+#' Returns a `SpatRaster` object (terra package).
+#'
+#' @param routes An sf object containing linestring geometries
+#' @param ... Additional arguments passed to ceramic::cc_elevation
+#' @return A SpatRaster covering the routes
+#' @export
+elevation_get <- function(routes, ...) {
+  if (!requireNamespace("ceramic", quietly = TRUE)) {
+    stop("Install the package ceramic to use elevation_get().")
+  }
+  mid_ext <- sf_mid_ext_lonlat(routes)
+  bw <- max(c(mid_ext$width, mid_ext$height)) / 1 # buffer width
+  suppressWarnings({
+    e <- ceramic::cc_elevation(loc = mid_ext$midpoint, buffer = bw, ...)
+  })
+  crs_routes <- sf::st_crs(routes)
+  terra::project(e, y = crs_routes$wkt)
+}
+
+#' Extract midpoint and extent from routes in lonlat
+#'
+#' Internal helper function to get midpoint and extent of routes in lon/lat
+#' coordinates.
+#'
+#' @param routes An sf object containing linestring geometries
+#' @return A list with midpoint coordinates and width/height dimensions
+sf_mid_ext_lonlat <- function(routes) {
+  res <- list()
+  if (!sf::st_is_longlat(routes)) {
+    routes <- sf::st_transform(routes, 4326)
+  }
+  bb <- sf::st_bbox(routes)
+  res$midpoint <- c(mean(c(bb[1], bb[3])), mean(c(bb[2], bb[4])))
+  res$width <- geodist::geodist(c(x = bb[1], y = bb[2]), c(x = bb[3], y = bb[2]))
+  res$height <- geodist::geodist(
+    c(x = bb[1], y = bb[2]),
+    c(x = bb[1], y = bb[4])
+  )
+  res
+}
+
+# ── elevation_extract ────────────────────────────────────────────────────────
+
+#' Extract elevation values from coordinates
+#'
+#' Extracts elevation values from a DEM raster at specified coordinate locations.
+#' Accepts both `SpatRaster` (terra) and legacy `Raster*` (raster) objects;
+#' legacy objects are automatically converted to `SpatRaster`.
+#'
+#' @param m Matrix or sf object with coordinates
+#' @param dem A SpatRaster (or legacy RasterLayer) containing elevation data
+#' @param method Method for raster extraction (default: "bilinear")
+#' @param terra Deprecated. Ignored; terra is always used.
+#' @return Numeric vector of elevation values
+#' @export
+elevation_extract <- function(m, dem, method = "bilinear", terra = NULL) {
+  if (!is.null(terra)) {
+    .Deprecated(msg = "The 'terra' argument is deprecated and ignored. terra is always used.")
+  }
+  if (any(grepl(pattern = "sf", class(m)))) m <- sf::st_coordinates(m)
+  if (!methods::is(dem, "SpatRaster")) {
+    if (requireNamespace("terra", quietly = TRUE)) {
+      message("Converting legacy Raster* object to SpatRaster. Consider using terra::rast() directly.")
+      dem <- terra::rast(dem)
+    } else {
+      stop("terra package is required. Install it with: install.packages('terra')")
+    }
+  }
+  terra::extract(dem, m[, 1:2], method = method)[[1]]
+}
+
+# ── elevation_add ────────────────────────────────────────────────────────────
+
+#' Add elevation data to routes linestrings or points
+#'
+#' Adds elevation data to sf objects using a digital elevation model (DEM).
+#'
+#' For **linestring** geometries, the function attaches elevation as the Z
+#' coordinate of each vertex, returning an XYZ linestring sf object.
+#'
+#' For **point** geometries, the function embeds the Z coordinate directly in
+#' the geometry by default (returning POINT Z features), consistent with the
+#' linestring behaviour. An `elevation` column can additionally be added by
+#' setting `add_column = TRUE`.
+#'
+#' @param routes An sf object containing linestring or point geometries.
+#' @param dem A SpatRaster object containing elevation data
+#'   (default: `NULL` for automatic download via `elevation_get()`).
+#' @param method Method for raster extraction (default: `"bilinear"`).
+#' @param add_z For **point** geometries only: if `TRUE` (the default), the Z
+#'   coordinate is embedded directly in the point geometry, returning POINT Z
+#'   features. Set to `FALSE` to keep the original XY geometry. Ignored for
+#'   linestrings (Z is always added to linestring vertices).
+#' @param add_column For **point** geometries only: if `TRUE`, an `elevation`
+#'   column is added to the returned sf object in addition to (or instead of,
+#'   when `add_z = FALSE`) the Z geometry. Default: `FALSE`. Ignored for
+#'   linestrings.
+#' @param terra Deprecated. Ignored; terra is always used.
+#' @return An sf object. For linestrings: XYZ linestring geometries. For points:
+#'   POINT Z geometry (when `add_z = TRUE`) and/or an `elevation` column (when
+#'   `add_column = TRUE`).
+#' @export
+#' @examples
+#' library(sf)
+#' # Linestring usage:
+#' routes <- lisbon_road_network[204, ]
+#' dem <- dem_lisbon()
+#' (r3d <- elevation_add(routes, dem))
+#' st_z_range(r3d)
+#' plot(st_coordinates(r3d)[, 3])
+#' plot_slope(r3d)
+#' # Point usage — Z embedded in geometry by default:
+#' pts <- sf::st_cast(sf::st_geometry(lisbon_road_network[204, ]), "POINT")
+#' pts <- sf::st_sf(id = seq_along(pts), geometry = pts)
+#' (pts_z <- elevation_add(pts, dem))
+#' sf::st_z_range(pts_z)
+#' # Also add an elevation column:
+#' (pts_z_col <- elevation_add(pts, dem, add_column = TRUE))
+#' pts_z_col$elevation
+#' # Only an elevation column, keep XY geometry:
+#' (pts_col <- elevation_add(pts, dem, add_z = FALSE, add_column = TRUE))
+#' \dontrun{
+#' # Get elevation data (requires internet connection, ceramic pkg, and API key):
+#' if (requireNamespace("ceramic", quietly = TRUE)) {
+#'   r3d_get <- elevation_add(cyclestreets_route)
+#'   plot_slope(r3d_get)
+#' }
+#' }
+elevation_add <- function(routes, dem = NULL, method = "bilinear",
+                          add_z = TRUE, add_column = FALSE,
+                          terra = NULL) {
+  if (!is.null(terra)) {
+    .Deprecated(msg = "The 'terra' argument is deprecated and ignored. terra is always used.")
+  }
+  stopifnotsf(routes)
+
+  geom_types <- unique(sf::st_geometry_type(routes))
+
+  # ── POINT branch ────────────────────────────────────────────────────────────
+  if (all(geom_types %in% c("POINT", "MULTIPOINT"))) {
+    if (is.null(dem)) {
+      dem <- elevation_get(routes)
+      r_original <- routes
+      routes <- sf::st_transform(routes, terra::crs(dem))
+      suppressWarnings({
+        sf::st_crs(routes) <- sf::st_crs(r_original)
+      })
+      m <- sf::st_coordinates(routes)
+      mo <- sf::st_coordinates(r_original)
+      z <- as.numeric(elevation_extract(m, dem, method = method))
+      routes <- r_original # restore original CRS / coords
+    } else {
+      m <- sf::st_coordinates(routes)
+      z <- as.numeric(elevation_extract(m, dem, method = method))
+      mo <- m
+    }
+    if (add_column) {
+      routes$elevation <- z
+    }
+    if (add_z) {
+      m_xyz <- cbind(mo[, 1:2], z)
+      points_z <- lapply(seq_len(nrow(m_xyz)), function(i) {
+        sf::st_point(m_xyz[i, ], dim = "XYZ")
+      })
+      sf::st_geometry(routes) <- sf::st_sfc(points_z, crs = sf::st_crs(routes))
+    }
+    return(routes)
+  }
+
+  # ── LINESTRING branch ────────────────────────────────────────────────────────
+  if (is.null(dem)) {
+    dem <- elevation_get(routes) # returns SpatRaster
+    r_original <- routes
+    routes <- sf::st_transform(routes, terra::crs(dem))
+    suppressWarnings({
+      sf::st_crs(routes) <- sf::st_crs(r_original)
+    })
+    m <- sf::st_coordinates(routes)
+    mo <- sf::st_coordinates(r_original)
+    z <- as.numeric(elevation_extract(m, dem, method = method))
+    m_xyz <- cbind(mo[, 1:2], z)
+  } else {
+    m <- sf::st_coordinates(routes)
+    z <- as.numeric(elevation_extract(m, dem, method = method))
+    m_xyz <- cbind(m[, 1:2], z)
+  }
+  n <- nrow(routes)
+  linestrings <- lapply(seq(n), function(i) sf::st_linestring(m_xyz[m[, "L1"] == i, ]))
+  rgeom3d_sfc <- sf::st_sfc(linestrings, crs = sf::st_crs(routes))
+  sf::st_geometry(routes) <- rgeom3d_sfc
+  routes
+}
diff --git a/R/slope_get.R b/R/slope_get.R
index 7b7d57e..c7e5ed5 100644
--- a/R/slope_get.R
+++ b/R/slope_get.R
@@ -1,46 +1,4 @@
-#' Get elevation data for routes
-#'
-#' Downloads elevation data using the ceramic package for given routes.
-#' Returns a `SpatRaster` object (terra package).
-#'
-#' @param routes An sf object containing linestring geometries
-#' @param ... Additional arguments passed to ceramic::cc_elevation
-#' @return A SpatRaster covering the routes
-#' @export
-elevation_get = function(routes, ...) {
-  if (!requireNamespace("ceramic", quietly = TRUE)) {
-    stop("Install the package ceramic to use elevation_get().")
-  }
-  mid_ext = sf_mid_ext_lonlat(routes)
-  bw = max(c(mid_ext$width, mid_ext$height)) / 1 # buffer width
-  suppressWarnings({
-    e = ceramic::cc_elevation(loc = mid_ext$midpoint, buffer = bw, ...)
-  })
-  crs_routes = sf::st_crs(routes)
-  terra::project(e, y = crs_routes$wkt)
-}
-
-#' Extract midpoint and extent from routes in lonlat
-#'
-#' Internal helper function to get midpoint and extent of routes in lon/lat coordinates.
-#'
-#' @param routes An sf object containing linestring geometries
-#' @return A list with midpoint coordinates and width/height dimensions
-sf_mid_ext_lonlat = function(routes) {
-  res = list()
-  if(!sf::st_is_longlat(routes)) {
-    routes = sf::st_transform(routes, 4326)
-  }
-  bb = sf::st_bbox(routes)
-  res$midpoint = c(mean(c(bb[1], bb[3])), mean(c(bb[2], bb[4])))
-  res$width = geodist::geodist(c(x = bb[1], y = bb[2]), c(x = bb[3], y = bb[2]))
-  res$height = geodist::geodist(
-    c(x = bb[1], y = bb[2]),
-    c(x = bb[1], y = bb[4])
-  )
-  res
-}
-
+# Raster / matrix utility functions for slope data
 #' Convert slope matrix to SpatRaster
 #'
 #' Converts a slope matrix or a legacy RasterLayer to a SpatRaster (terra).
diff --git a/R/slopes.R b/R/slopes.R
index 2cb5b59..b1c1e4c 100644
--- a/R/slopes.R
+++ b/R/slopes.R
@@ -202,154 +202,6 @@ slope_xyz <- function(route_xyz, fun = slope_matrix_weighted, lonlat = TRUE, dir
   }
 }
 
-#' Extract elevation values from coordinates
-#'
-#' Extracts elevation values from a DEM raster at specified coordinate locations.
-#' Accepts both `SpatRaster` (terra) and legacy `Raster*` (raster) objects;
-#' legacy objects are automatically converted to `SpatRaster`.
-#'
-#' @param m Matrix or sf object with coordinates
-#' @param dem A SpatRaster (or legacy RasterLayer) containing elevation data
-#' @param method Method for raster extraction (default: "bilinear")
-#' @param terra Deprecated. Ignored; terra is always used.
-#' @return Numeric vector of elevation values
-#' @export
-elevation_extract <- function(m, dem, method = "bilinear", terra = NULL) {
-  if (!is.null(terra)) {
-    .Deprecated(msg = "The 'terra' argument is deprecated and ignored. terra is always used.")
-  }
-  if (any(grepl(pattern = "sf", class(m)))) m <- sf::st_coordinates(m)
-  if (!methods::is(dem, "SpatRaster")) {
-    if (requireNamespace("terra", quietly = TRUE)) {
-      message("Converting legacy Raster* object to SpatRaster. Consider using terra::rast() directly.")
-      dem <- terra::rast(dem)
-    } else {
-      stop("terra package is required. Install it with: install.packages('terra')")
-    }
-  }
-  terra::extract(dem, m[, 1:2], method = method)[[1]]
-}
-
-#' Add elevation data to routes linestrings or points
-#'
-#' Adds elevation data to sf objects using a digital elevation model (DEM).
-#'
-#' For **linestring** geometries, the function attaches elevation as the Z
-#' coordinate of each vertex, returning an XYZ linestring sf object.
-#'
-#' For **point** geometries, the function embeds the Z coordinate directly in
-#' the geometry by default (returning POINT Z features), consistent with the
-#' linestring behaviour. An `elevation` column can additionally be added by
-#' setting `add_column = TRUE`.
-#'
-#' @param routes An sf object containing linestring or point geometries.
-#' @param dem A SpatRaster object containing elevation data
-#'   (default: `NULL` for automatic download via `elevation_get()`).
-#' @param method Method for raster extraction (default: `"bilinear"`).
-#' @param add_z For **point** geometries only: if `TRUE` (the default), the Z
-#'   coordinate is embedded directly in the point geometry, returning POINT Z
-#'   features. Set to `FALSE` to keep the original XY geometry. Ignored for
-#'   linestrings (Z is always added to linestring vertices).
-#' @param add_column For **point** geometries only: if `TRUE`, an `elevation`
-#'   column is added to the returned sf object in addition to (or instead of,
-#'   when `add_z = FALSE`) the Z geometry. Default: `FALSE`. Ignored for
-#'   linestrings.
-#' @param terra Deprecated. Ignored; terra is always used.
-#' @return An sf object. For linestrings: XYZ linestring geometries. For points:
-#'   POINT Z geometry (when `add_z = TRUE`) and/or an `elevation` column (when
-#'   `add_column = TRUE`).
-#' @export
-#' @examples
-#' library(sf)
-#' # Linestring usage:
-#' routes <- lisbon_road_network[204, ]
-#' dem <- dem_lisbon()
-#' (r3d <- elevation_add(routes, dem))
-#' st_z_range(r3d)
-#' plot(st_coordinates(r3d)[, 3])
-#' plot_slope(r3d)
-#' # Point usage — Z embedded in geometry by default:
-#' pts <- sf::st_cast(sf::st_geometry(lisbon_road_network[204, ]), "POINT")
-#' pts <- sf::st_sf(id = seq_along(pts), geometry = pts)
-#' (pts_z <- elevation_add(pts, dem))
-#' sf::st_z_range(pts_z)
-#' # Also add an elevation column:
-#' (pts_z_col <- elevation_add(pts, dem, add_column = TRUE))
-#' pts_z_col$elevation
-#' # Only an elevation column, keep XY geometry:
-#' (pts_col <- elevation_add(pts, dem, add_z = FALSE, add_column = TRUE))
-#' \dontrun{
-#' # Get elevation data (requires internet connection, ceramic pkg, and API key):
-#' if (requireNamespace("ceramic", quietly = TRUE)) {
-#'   r3d_get <- elevation_add(cyclestreets_route)
-#'   plot_slope(r3d_get)
-#' }
-#' }
-elevation_add <- function(routes, dem = NULL, method = "bilinear",
-                          add_z = TRUE, add_column = FALSE,
-                          terra = NULL) {
-  if (!is.null(terra)) {
-    .Deprecated(msg = "The 'terra' argument is deprecated and ignored. terra is always used.")
-  }
-  stopifnotsf(routes)
-
-  geom_types <- unique(sf::st_geometry_type(routes))
-
-  # ── POINT branch ────────────────────────────────────────────────────────────
-  if (all(geom_types %in% c("POINT", "MULTIPOINT"))) {
-    if (is.null(dem)) {
-      dem <- elevation_get(routes)
-      r_original <- routes
-      routes <- sf::st_transform(routes, terra::crs(dem))
-      suppressWarnings({
-        sf::st_crs(routes) <- sf::st_crs(r_original)
-      })
-      m <- sf::st_coordinates(routes)
-      mo <- sf::st_coordinates(r_original)
-      z <- as.numeric(elevation_extract(m, dem, method = method))
-      routes <- r_original # restore original CRS / coords
-    } else {
-      m <- sf::st_coordinates(routes)
-      z <- as.numeric(elevation_extract(m, dem, method = method))
-      mo <- m
-    }
-    if (add_column) {
-      routes$elevation <- z
-    }
-    if (add_z) {
-      m_xyz <- cbind(mo[, 1:2], z)
-      points_z <- lapply(seq_len(nrow(m_xyz)), function(i) {
-        sf::st_point(m_xyz[i, ], dim = "XYZ")
-      })
-      sf::st_geometry(routes) <- sf::st_sfc(points_z, crs = sf::st_crs(routes))
-    }
-    return(routes)
-  }
-
-  # ── LINESTRING branch ────────────────────────────────────────────────────────
-  if (is.null(dem)) {
-    dem <- elevation_get(routes) # returns SpatRaster
-    r_original <- routes
-    routes <- sf::st_transform(routes, terra::crs(dem))
-    suppressWarnings({
-      sf::st_crs(routes) <- sf::st_crs(r_original)
-    })
-    m <- sf::st_coordinates(routes)
-    mo <- sf::st_coordinates(r_original)
-    z <- as.numeric(elevation_extract(m, dem, method = method))
-    m_xyz <- cbind(mo[, 1:2], z)
-  } else {
-    m <- sf::st_coordinates(routes)
-    z <- as.numeric(elevation_extract(m, dem, method = method))
-    m_xyz <- cbind(m[, 1:2], z)
-  }
-  n <- nrow(routes)
-  linestrings <- lapply(seq(n), function(i) sf::st_linestring(m_xyz[m[, "L1"] == i, ]))
-  rgeom3d_sfc <- sf::st_sfc(linestrings, crs = sf::st_crs(routes))
-  sf::st_geometry(routes) <- rgeom3d_sfc
-  routes
-}
-
 # Utility functions
 has_terra <- function() requireNamespace("terra", quietly = TRUE)
 is_linestring <- function(x) unique(sf::st_geometry_type(x)) == "LINESTRING"
@@ -377,3 +229,4 @@ route_to_segments <- function(route_xyz) {
   segs <- lapply(seq_len(n - 1), function(i) sf::st_linestring(coords[i:(i + 1), 1:3]))
   sf::st_sf(geometry = sf::st_sfc(segs, crs = sf::st_crs(route_xyz)))
 }
+
diff --git a/R/z-functions.R b/R/z-functions.R
deleted file mode 100644
index 89d9116..0000000
--- a/R/z-functions.R
+++ /dev/null
@@ -1,32 +0,0 @@
-
-z_value <- function(x) {
-  coords <- sf::st_coordinates(x)
-  if("Z" %in% colnames(coords)) {
-    return(coords[, "Z"])
-  } else {
-    stop("No Z coordinates found in the input data")
-  }
-}
-
-z_mean <- function(x) {
-  mean(z_value(x), na.rm = TRUE)
-}
-
-z_min <- function(x) {
-  min(z_value(x), na.rm = TRUE)
-}
-
-z_max <- function(x) {
-  max(z_value(x), na.rm = TRUE)
-}
-
-z_start <- function(x) {
-  z_vals <- z_value(x)
-  z_vals[1]
-}
-
-z_end <- function(x) {
-  z_vals <- z_value(x)
-  z_vals[length(z_vals)]
-}
-
diff --git a/tests/testthat/Rplots.pdf b/tests/testthat/Rplots.pdf
index 45f1c389d5edf9d04b31ed04cb16eebea237e73b..6353f1376c8a6d0dcd2600c1f975febfe002f11b 100644
GIT binary patch
delta 23
bcmbO&Gh1eYHH)dKk;O!N2{64e`T#EgPr?SP

delta 23
bcmbO&Gh1eYHH)!@vFSv62{64e`T#EgPqGH7

diff --git a/tests/testthat/test-elevation.R b/tests/testthat/test-elevation.R
new file mode 100644
index 0000000..4223301
--- /dev/null
+++ b/tests/testthat/test-elevation.R
@@ -0,0 +1,88 @@
+test_that("functions to get elevations from sf objects work", {
+  if(nchar(Sys.getenv("MAPBOX_API_KEY")) < 8)
+    skip(message = "Skipping test, MAPBOX token in .Renviron needed")
+  r = cyclestreets_route
+  e = elevation_get(r)
+  expect_true(methods::is(e, "SpatRaster"))
+})
+
+test_that("elevation_extract() works", {
+  m = sf::st_coordinates(lisbon_road_segment)
+  e = elevation_extract(m, dem_lisbon())
+  expect_identical(round(e[1:3], 2), c(92.31, 91.93, 91.60))
+  e = elevation_extract(lisbon_road_segment, dem_lisbon())
+  expect_identical(round(e[1:3], 2), c(92.31, 91.93, 91.60))
+})
+
+test_that("elevation_add() works with LINESTRING geometries", {
+  e = dem_lisbon()
+  r = lisbon_road_network[204, ]
+  r3d = elevation_add(r, e)
+  expect_equal(
+    sf::st_z_range(r3d$geom),
+    c(86, 92),
+    ignore_attr = TRUE,
+    tolerance = 10
+    )
+  if(nchar(Sys.getenv("MAPBOX_API_KEY")) < 8)
+    skip(message = "Skipping test, MAPBOX token in .Renviron needed")
+  r3d2 = elevation_add(r)
+  expect_equal(
+    sf::st_z_range(r3d2$geom),
+    c(86, 92),
+    ignore_attr = TRUE,
+    tolerance = 10
+    )
+})
+
+test_that("elevation_add() works with POINT geometries", {
+  dem <- dem_lisbon()
+  pts <- sf::st_cast(sf::st_geometry(lisbon_road_network[204, ]), "POINT")
+  pts <- sf::st_sf(id = seq_along(pts), geometry = pts)
+
+  # Default: add_z = TRUE, no elevation column
+  pts_z <- elevation_add(pts, dem)
+  expect_s3_class(pts_z, "sf")
+  expect_equal(as.character(sf::st_geometry_type(pts_z)[1]), "POINT")
+  expect_true(!is.na(sf::st_z_range(pts_z)[1]))      # has Z coordinate
+  expect_false("elevation" %in% names(pts_z))
+  expect_equal(
+    sf::st_z_range(pts_z),
+    c(86, 92),
+    ignore_attr = TRUE,
+    tolerance = 10
+  )
+
+  # add_column = TRUE: Z in geometry AND elevation column
+  pts_z_col <- elevation_add(pts, dem, add_column = TRUE)
+  expect_true("elevation" %in% names(pts_z_col))
+  expect_true(!is.na(sf::st_z_range(pts_z_col)[1]))  # still has Z
+  expect_equal(
+    round(pts_z_col$elevation[1:3], 2),
+    c(92.31, 91.93, 91.60)
+  )
+
+  # add_z = FALSE, add_column = TRUE: XY geometry with elevation column
+  pts_col <- elevation_add(pts, dem, add_z = FALSE, add_column = TRUE)
+  expect_true("elevation" %in% names(pts_col))
+  expect_true(is.null(sf::st_z_range(pts_col)))      # XY: no Z coordinate
+  expect_equal(
+    round(pts_col$elevation[1:3], 2),
+    c(92.31, 91.93, 91.60)
+  )
+})
+
+test_that("Functions on Z values work", {
+  x = slopes::lisbon_route_3d
+  expect_equal(class(z_value(x)), "numeric")
+  x = slopes::lisbon_route
+  expect_error(z_value(x))
+  expect_error(z_start(x))
+  expect_error(z_end(x))
+  expect_error(z_mean(x))
+  expect_error(z_min(x))
+  expect_error(z_max(x))
+  expect_error(z_elevation_change_start_end(x))
+  expect_error(z_direction(x))
+  expect_error(z_cumulative_difference(x))
+})
diff --git a/tests/testthat/test-get.R b/tests/testthat/test-get.R
deleted file mode 100644
index 3bec16d..0000000
--- a/tests/testthat/test-get.R
+++ /dev/null
@@ -1,8 +0,0 @@
-test_that("functions to get elevations from sf objects work", {
-  if(nchar(Sys.getenv("MAPBOX_API_KEY")) < 8)
-    skip(message = "Skipping test, MAPBOX token in .Renviron needed")
-  r = cyclestreets_route
-  e = elevation_get(r)
-  expect_true(methods::is(e, "SpatRaster"))
-})
-
diff --git a/tests/testthat/test-slopes.R b/tests/testthat/test-slopes.R
index 01a1f08..a5fc1a8 100644
--- a/tests/testthat/test-slopes.R
+++ b/tests/testthat/test-slopes.R
@@ -13,9 +13,6 @@ test_that("slope_* functions work", {
   expect_true(sequential_right)
 
   e = elevation_extract(m, dem_lisbon())
-  expect_identical(round(e[1:3], 2), c(92.31, 91.93, 91.60))
-  e = elevation_extract(lisbon_road_segment, dem_lisbon())
-  expect_identical(round(e[1:3], 2), c(92.31, 91.93, 91.60))
   s = slope_distance(d, e)
   expect_identical(round(s[1:3], 3), c(-0.047, -0.041, -0.025))
 
@@ -64,62 +61,10 @@ test_that("slope_* functions work", {
   r_xyz = lisbon_road_segment_3d
   expect_equal(slope_xyz(r_xyz), 0.0950132312274622, ignore_attr = TRUE)
 
-  r = lisbon_road_network[204, ]
-  r3d = elevation_add(r, e)
-  expect_equal(
-    sf::st_z_range(r3d$geom),
-    c(86, 92),
-    ignore_attr = TRUE,
-    tolerance = 10
-    )
-  if(nchar(Sys.getenv("MAPBOX_API_KEY")) < 8)
-    skip(message = "Skipping test, MAPBOX token in .Renviron needed")
-  r3d2 = elevation_add(r)
-  expect_equal(
-    sf::st_z_range(r3d2$geom),
-    c(86, 92),
-    ignore_attr = TRUE,
-    tolerance = 10
-    )
+
 
   expect_error(slopes:::stopifnotsf(1))
   expect_error(slopes:::stop_is_not_linestring(1))
 
 })
 
-test_that("elevation_add() works with POINT geometries", {
-  dem <- dem_lisbon()
-  pts <- sf::st_cast(sf::st_geometry(lisbon_road_network[204, ]), "POINT")
-  pts <- sf::st_sf(id = seq_along(pts), geometry = pts)
-
-  # Default: add_z = TRUE, no elevation column
-  pts_z <- elevation_add(pts, dem)
-  expect_s3_class(pts_z, "sf")
-  expect_equal(as.character(sf::st_geometry_type(pts_z)[1]), "POINT")
-  expect_true(!is.na(sf::st_z_range(pts_z)[1]))      # has Z coordinate
-  expect_false("elevation" %in% names(pts_z))
-  expect_equal(
-    sf::st_z_range(pts_z),
-    c(86, 92),
-    ignore_attr = TRUE,
-    tolerance = 10
-  )
-
-  # add_column = TRUE: Z in geometry AND elevation column
-  pts_z_col <- elevation_add(pts, dem, add_column = TRUE)
-  expect_true("elevation" %in% names(pts_z_col))
-  expect_true(!is.na(sf::st_z_range(pts_z_col)[1]))  # still has Z
-  expect_equal(
-    round(pts_z_col$elevation[1:3], 2),
-    c(92.31, 91.93, 91.60)
-  )
-
-  # add_z = FALSE, add_column = TRUE: XY geometry with elevation column
-  pts_col <- elevation_add(pts, dem, add_z = FALSE, add_column = TRUE)
-  expect_true("elevation" %in% names(pts_col))
-  expect_true(is.null(sf::st_z_range(pts_col)))      # XY: no Z coordinate
-  expect_equal(
-    round(pts_col$elevation[1:3], 2),
-    c(92.31, 91.93, 91.60)
-  )
-})
diff --git a/tests/testthat/test-z.R b/tests/testthat/test-z.R
deleted file mode 100644
index 1c1f4e8..0000000
--- a/tests/testthat/test-z.R
+++ /dev/null
@@ -1,16 +0,0 @@
-test_that("Functions on Z values work", {
-  x = slopes::lisbon_route_3d
-  expect_equal(class(z_value(x)), "numeric")
-  x = slopes::lisbon_route
-  expect_error(z_value(x))
-  expect_error(z_start(x))
-  expect_error(z_end(x))
-  expect_error(z_mean(x))
-  expect_error(z_min(x))
-  expect_error(z_max(x))
-  expect_error(z_elevation_change_start_end(x))
-  expect_error(z_direction(x))
-  expect_error(z_cumulative_difference(x))
-  # x_slope =
-  # expect_is()
-})

From 01cf9d3aa706923c0705f7b4103a438df1c5a9c8 Mon Sep 17 00:00:00 2001
From: RFlx <temospena@gmail.com>
Date: Mon, 22 Jun 2026 14:02:49 +0100
Subject: [PATCH 4/4] update documentation for elevation_add with points #21

---
 man/elevation_add.Rd     |  2 +-
 man/elevation_extract.Rd |  2 +-
 man/elevation_get.Rd     |  2 +-
 man/sf_mid_ext_lonlat.Rd |  5 +++--
 vignettes/slopes.Rmd     | 10 +++++++---
 5 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/man/elevation_add.Rd b/man/elevation_add.Rd
index b2efeea..4b7e0bf 100644
--- a/man/elevation_add.Rd
+++ b/man/elevation_add.Rd
@@ -1,5 +1,5 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/slopes.R
+% Please edit documentation in R/elevation.R
 \name{elevation_add}
 \alias{elevation_add}
 \title{Add elevation data to routes linestrings or points}
diff --git a/man/elevation_extract.Rd b/man/elevation_extract.Rd
index cbf8367..17b637b 100644
--- a/man/elevation_extract.Rd
+++ b/man/elevation_extract.Rd
@@ -1,5 +1,5 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/slopes.R
+% Please edit documentation in R/elevation.R
 \name{elevation_extract}
 \alias{elevation_extract}
 \title{Extract elevation values from coordinates}
diff --git a/man/elevation_get.Rd b/man/elevation_get.Rd
index 072fb58..b0d353c 100644
--- a/man/elevation_get.Rd
+++ b/man/elevation_get.Rd
@@ -1,5 +1,5 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/slope_get.R
+% Please edit documentation in R/elevation.R
 \name{elevation_get}
 \alias{elevation_get}
 \title{Get elevation data for routes}
diff --git a/man/sf_mid_ext_lonlat.Rd b/man/sf_mid_ext_lonlat.Rd
index 1b813cd..c5362d5 100644
--- a/man/sf_mid_ext_lonlat.Rd
+++ b/man/sf_mid_ext_lonlat.Rd
@@ -1,5 +1,5 @@
 % Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/slope_get.R
+% Please edit documentation in R/elevation.R
 \name{sf_mid_ext_lonlat}
 \alias{sf_mid_ext_lonlat}
 \title{Extract midpoint and extent from routes in lonlat}
@@ -13,5 +13,6 @@ sf_mid_ext_lonlat(routes)
 A list with midpoint coordinates and width/height dimensions
 }
 \description{
-Internal helper function to get midpoint and extent of routes in lon/lat coordinates.
+Internal helper function to get midpoint and extent of routes in lon/lat
+coordinates.
 }
diff --git a/vignettes/slopes.Rmd b/vignettes/slopes.Rmd
index d0dae5e..11f9438 100644
--- a/vignettes/slopes.Rmd
+++ b/vignettes/slopes.Rmd
@@ -101,7 +101,7 @@ data(lisbon_route)
 dem_lisbon <- dem_lisbon()
 ```
 
-## Add elevation to a linestring
+## Add elevation to linestrings or points
 
 If you have a 2D linestring and a DEM, you can add elevation data to the linestring using `elevation_add()`:
 
@@ -118,6 +118,8 @@ If you don't have a local DEM, `elevation_add()` can download elevation data (th
 # head(sf::st_coordinates(sf_linestring_xyz_mapbox))
 ```
 
+You can also use `elevation_add()` with points.
+
 ## Calculate slope
 
 Once you have a 3D linestring (with XYZ coordinates), you can calculate its average slope using `slope_xyz()`:
@@ -157,7 +159,8 @@ summary(lisbon_route_segments_xyz$slope)
 # Segments are coloured by steepness (absolute slope), regardless of direction
 # (uphill or downhill). slope_breaks are in proportions, matching slope_xyz() output.
 col_idx <- cut(abs(lisbon_route_segments_xyz$slope),
-  breaks = slope_breaks, labels = FALSE, include.lowest = TRUE)
+  breaks = slope_breaks, labels = FALSE, include.lowest = TRUE
+)
 plot(st_geometry(lisbon_route_segments_xyz),
   col = slope_colors[col_idx],
   lwd = 3, main = "Slope by vertex segments"
@@ -178,7 +181,8 @@ summary(lisbon_route_100m_xyz$slope)
 
 ```{r}
 col_idx <- cut(abs(lisbon_route_100m_xyz$slope),
-  breaks = slope_breaks, labels = FALSE, include.lowest = TRUE)
+  breaks = slope_breaks, labels = FALSE, include.lowest = TRUE
+)
 plot(st_geometry(lisbon_route_100m_xyz),
   col = slope_colors[col_idx],
   lwd = 3, main = "Slope by 100 m segments"