Calculates and returns an overlay of lines for the current height map.
generate_line_overlay(
geometry,
extent,
heightmap = NULL,
width = NA,
height = NA,
resolution_multiply = 1,
color = "black",
linewidth = 1,
lty = 1,
data_column_width = NULL,
offset = c(0, 0)
)Arguments
- geometry
An `sf` object with LINESTRING geometry.
- extent
Either an object representing the spatial extent of the scene (either from the `raster`, `terra`, `sf`, or `sp` packages), a length-4 numeric vector specifying `c("xmin", "xmax","ymin","ymax")`, or the spatial object (from the previously aforementioned packages) which will be automatically converted to an extent object.
- heightmap
Default `NULL`. The original height map. Pass this in to extract the dimensions of the resulting overlay automatically.
- width
Default `NA`. Width of the resulting overlay. Default the same dimensions as height map.
- height
Default `NA`. Width of the resulting overlay. Default the same dimensions as height map.
- resolution_multiply
Default `1`. If passing in `heightmap` instead of width/height, amount to increase the resolution of the overlay, which should make lines/polygons/text finer. Should be combined with `add_overlay(rescale_original = TRUE)` to ensure those added details are captured in the final map.
- color
Default `black`. Color of the lines.
- linewidth
Default `1`. Line width.
- lty
Default `1`. Line type. `1` is solid, `2` is dashed, `3` is dotted,`4` is dot-dash, `5` is long dash, and `6` is dash-long-dash.
- data_column_width
Default `NULL`. The numeric column to map the width to. The maximum width will be the value specified in `linewidth`.
- offset
Default `c(0,0)`. Horizontal and vertical offset to apply to the line, in units of `geometry`.
Value
Semi-transparent overlay with contours.
Examples
#Add the included `sf` object with roads to the montereybay dataset
if(run_documentation()) {
water_palette = colorRampPalette(c("darkblue", "dodgerblue", "lightblue"))(200)
bathy_hs = height_shade(montereybay, texture = water_palette)
montereybay %>%
height_shade() %>%
add_overlay(generate_altitude_overlay(bathy_hs, montereybay, 0, 0)) %>%
add_overlay(generate_line_overlay(monterey_roads_sf,
attr(montereybay,"extent"), heightmap = montereybay)) %>%
add_shadow(ray_shade(montereybay,zscale=50),0.3) %>%
plot_map()
}
if(run_documentation()) {
#Change the line width, color, and transparency
montereybay %>%
height_shade() %>%
add_overlay(generate_altitude_overlay(bathy_hs, montereybay, 0, 0)) %>%
add_overlay(generate_line_overlay(monterey_roads_sf, linewidth=3, color="white",
attr(montereybay,"extent"), heightmap = montereybay),
alphalayer=0.8) %>%
add_shadow(ray_shade(montereybay,zscale=50),0.3) %>%
plot_map()
}
if(run_documentation()) {
#Manually specify the width and height to improve visual quality of the lines
montereybay %>%
height_shade() %>%
add_overlay(generate_altitude_overlay(bathy_hs, montereybay, 0, 0)) %>%
add_shadow(ray_shade(montereybay,zscale=50),0.3) %>%
add_overlay(generate_line_overlay(monterey_roads_sf, linewidth=3, color="white",
attr(montereybay,"extent"), width = 1080, height = 1080),
alphalayer=0.8) %>%
plot_map()
}
