From 3d324fea1d2daa6204be8cb66b3bbe0256897dc3 Mon Sep 17 00:00:00 2001
From: Robin Lovelace <rob00x@gmail.com>
Date: Wed, 18 Aug 2021 22:50:29 +0100
Subject: [PATCH] Improve docs for elevation_get()

---
 R/slope_get.R        | 14 ++++++++++++--
 man/elevation_get.Rd | 18 +++++++++++++-----
 man/slope_raster.Rd  |  2 +-
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/R/slope_get.R b/R/slope_get.R
index 5c1afcc..c6f0961 100644
--- a/R/slope_get.R
+++ b/R/slope_get.R
@@ -1,11 +1,21 @@
 #' Get elevation data from hosted maptile services
 #'
+#' `elevation_get()` uses the `[ceramic::cc_elevation()]` function to get
+#' DEM data in raster format anywhere worldwide.
+#' It requires an API that can be added by following guidance in the package's
+#' [README](https://github.com/ITSLeeds/slopes#installation-for-dem-downloads).
+#'
+#'
+#' Note: if you use the `cc_elevation()` function directly to get DEM data,
+#' you can cache the data, as described in the package's
+#' [README](https://github.com/hypertidy/ceramic#local-caching-of-tiles).
+#'
 #' @param file Where to save the resulting data if specified (not implemented)
 #' @param ... Options passed to `cc_elevation()`
 #' @inheritParams slope_raster
 #' @export
 #' @examples
-#' # Time-consuming examples that require an internet connectioin and API key:
+#' # Time-consuming examples that require an internet connection and API key:
 #' \donttest{
 #' library(sf)
 #' library(raster)
@@ -16,7 +26,7 @@
 #' plot(e)
 #' plot(sf::st_geometry(routes), add = TRUE)
 #' }
-elevation_get = function(routes, file = NULL, ...) {
+elevation_get = function(routes, ...) {
   if(requireNamespace("ceramic")) {
     mid_ext = sf_mid_ext_lonlat(routes)
     bw = max(c(mid_ext$width, mid_ext$height)) / 1 # buffer width
diff --git a/man/elevation_get.Rd b/man/elevation_get.Rd
index 424e212..ad5384e 100644
--- a/man/elevation_get.Rd
+++ b/man/elevation_get.Rd
@@ -4,21 +4,29 @@
 \alias{elevation_get}
 \title{Get elevation data from hosted maptile services}
 \usage{
-elevation_get(routes, file = NULL, ...)
+elevation_get(routes, ...)
 }
 \arguments{
 \item{routes}{Routes, the gradients of which are to be calculated.
 The object must be of class \code{sf} with \code{LINESTRING} geometries.}
 
-\item{file}{Where to save the resulting data if specified (not implemented)}
-
 \item{...}{Options passed to \code{cc_elevation()}}
+
+\item{file}{Where to save the resulting data if specified (not implemented)}
 }
 \description{
-Get elevation data from hosted maptile services
+\code{elevation_get()} uses the \verb{[ceramic::cc_elevation()]} function to get
+DEM data in raster format anywhere worldwide.
+It requires an API that can be added by following guidance in the package's
+\href{https://github.com/ITSLeeds/slopes#installation-for-dem-downloads}{README}.
+}
+\details{
+Note: if you use the \code{cc_elevation()} function directly to get DEM data,
+you can cache the data, as described in the package's
+\href{https://github.com/hypertidy/ceramic#local-caching-of-tiles}{README}.
 }
 \examples{
-# Time-consuming examples that require an internet connectioin and API key:
+# Time-consuming examples that require an internet connection and API key:
 \donttest{
 library(sf)
 library(raster)
diff --git a/man/slope_raster.Rd b/man/slope_raster.Rd
index 23f3084..a88dd3e 100644
--- a/man/slope_raster.Rd
+++ b/man/slope_raster.Rd
@@ -6,7 +6,7 @@
 \usage{
 slope_raster(
   routes,
-  dem = NULL,
+  dem,
   lonlat = sf::st_is_longlat(routes),
   method = "bilinear",
   fun = slope_matrix_weighted,