Add elevation data to route linestrings

Adds elevation (Z) coordinates to linestring geometries using DEM data.

Usage

elevation_add(
  routes,
  dem = NULL,
  method = "bilinear",
  terra = has_terra() && methods::is(dem, "SpatRaster")
)

Arguments

routes

An sf object containing linestring geometries

dem

A raster object containing elevation data (default: NULL for automatic download)

method

Method for raster extraction (default: "bilinear")

terra

Logical, whether to use terra package (default: auto-detected)

Value

An sf object with XYZ linestring geometries

Examples

library(sf)
#> Linking to GEOS 3.12.1, GDAL 3.8.4, PROJ 9.4.0; sf_use_s2() is TRUE
routes = lisbon_road_network[204, ]
dem = dem_lisbon_raster
#> Loading required namespace: raster
(r3d = elevation_add(routes, dem))
#> Simple feature collection with 1 feature and 7 fields
#> Geometry type: LINESTRING
#> Dimension:     XYZ
#> Bounding box:  xmin: -87080.48 ymin: -105629.6 xmax: -87056.99 ymax: -105506.3
#> z_range:       zmin: 86.49414 zmax: 92.31126
#> Projected CRS: ETRS89 / Portugal TM06
#> # A tibble: 1 × 8
#>   OBJECTID Z_Min Z_Max Z_Mean Min_Slope Max_Slope Avg_Slope
#> *    <int> <dbl> <dbl>  <dbl>     <dbl>     <dbl>     <dbl>
#> 1     2997  86.5  92.3   89.9     0.334      32.0      7.49
#> # ℹ 1 more variable: geom <LINESTRING [m]>
st_z_range(routes)
#> NULL
st_z_range(r3d)
#>     zmin     zmax 
#> 86.49414 92.31126 
plot(st_coordinates(r3d)[, 3])

plot_slope(r3d)

if (FALSE) { # \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)
}
} # }